diff --git a/lib/strconv/ftos.ww b/lib/strconv/ftos.ww
index 91223556..417818f7 100644
--- a/lib/strconv/ftos.ww
+++ b/lib/strconv/ftos.ww
@@ -4,15 +4,14 @@
 // https://doi.org/10.1145/3192366.3192369 — Hare translated it from the
 // reference C (https://github.com/ulfjack/ryu); ww follows Hare.
 //
-// SCOPE — the f64tos shortest-representation subset (Hare's ffmt::G,
-// prec=void, fflags::NONE). Two deferrals:
-//   - f32tos (ftos.ha:448) + its f32 Ryū sub-path (f32todecf32 +
-//     mulpow5inv/pow5_divpow2 + mulshift32 + the *32 helpers + the
-//     F32_POW5_*_BITCOUNT defs) → fold-5b (task #67), gated on the #143
-//     f32-arg-push cgen fix: f32tos must call math.f32bits(n), passing
-//     an f32 arg, which spills MOVSD (cstage) vs MOVSS (wwstage) →
-//     990-997 byte-id break. Not isolatable (f32bits IS the reinterpret),
-//     only fixable. f32tos IS a real Hare entry — it ships in #67.
+// SCOPE — the f64tos + f32tos shortest-representation subset (Hare's
+// ffmt::G, prec=void, fflags::NONE). f32tos (ftos.ha:448) + its f32 Ryū
+// sub-path (f32todecf32 + mulpow5inv/pow5_divpow2 + mulshift32 + the *32
+// helpers, reusing the shared u64-core + the f64 SPLIT2 tables — the f32
+// path has no separate tables, matching ftos_ryu.ha) ship here in fold-5b
+// (task #67): the gating #143 f32-arg-push cgen fix landed (aff7725, MOVSS
+// both stages), so f32tos's math.f32bits(n) call — passing an f32 arg — is
+// now byte-id-clean. One deferral remains:
 //   - the parametric fftosf/ffmt/fflags/ftosf surface → task #64 (needs
 //     io::handle/memio + a `(size|io::error)?` per appendrune (#158);
 //     for G/void/NONE the ffmt/fflags/precision/multiprecision-fallback
@@ -340,6 +339,195 @@ fn f64todecf64(mantissa: u64, exponent: u32) decf64 = {
 	return decf64 { exponent = (exp: i64), mantissa = output };
 };
 
+// ==== f32 Ryū sub-path (ftos_ryu.ha). The *32 helpers below mirror their
+// u64 siblings at 32-bit width; they reuse the SHARED f64computeinvpow5/
+// f64computepow5 (and thus the f64 SPLIT2 tables) per ftos_ryu.ha — there
+// is no separate f32 table. Same scalar-PARAM-mutation → copy-to-local,
+// comma-split, assert → os.assert, expr-yield → block divergences as the
+// f64 path above. ====
+
+// ref/hare/strconv/ftos_ryu.ha:52. Largest p with 5^p | value (32-bit).
+fn pow5fac32(v: u32) u32 = {
+	let value: u32 = v;
+	let count: u32 = 0u32;
+	for (true) {
+		os.assert(value != 0u32, "strconv.pow5fac32: value == 0");
+		let q: u32 = value / 5u32;
+		let r: u32 = value % 5u32;
+		if (r != 0u32) { break; };
+		value = q;
+		count += 1u32;
+	};
+	return count;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:67.
+fn pow5multiple32(v: u32, p: u32) bool = { return pow5fac32(v) >= p; };
+
+// ref/hare/strconv/ftos_ryu.ha:75.
+fn pow2multiple32(v: u32, p: u32) bool = {
+	os.assert(v > 0u32, "strconv.pow2multiple32: v == 0");
+	os.assert(p < 32u32, "strconv.pow2multiple32: p >= 32");
+	return (v & ((1u32 << p) - 1u32)) == 0u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:121. `m * a_lo` etc. carry an explicit
+// (m: u64) cast (Hare promotes the u32 operand; ww is strict). The bound
+// assert inlines U32_MAX's value: ww's types.U32_MAX is package-private
+// (lib/types/types.ww — no `export`), so Hare's `types::U32_MAX` can't be
+// referenced cross-package.
+fn mulshift32(m: u32, a: u64, s: u32) u32 = {
+	os.assert(s > 32u32, "strconv.mulshift32: s <= 32");
+	let a_lo: u64 = (a: u32): u64;
+	let a_hi: u64 = a >> 32u64;
+	let b0: u64 = (m: u64) * a_lo;
+	let b1: u64 = (m: u64) * a_hi;
+	let sum: u64 = (b0 >> 32u64) + b1;
+	let ss: u64 = sum >> ((s: u64) - 32u64);
+	os.assert(ss <= 4294967295u64, "strconv.mulshift32: ss > U32_MAX");
+	return ss: u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:130.
+fn mulpow5inv_divpow2(m: u32, q: u32, j: i32) u32 = {
+	let pow5 = f64computeinvpow5(q);
+	return mulshift32(m, pow5.1 + 1u64, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:135.
+fn mulpow5_divpow2(m: u32, i: u32, j: i32) u32 = {
+	let pow5 = f64computepow5(i);
+	return mulshift32(m, pow5.1, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:387. `exponent` rides i64 not Hare's i32,
+// for the same reason decf64 does: widening the field to a full second
+// eightbyte SIDESTEPS the #169 narrow-i32-field struct-return unpack (a
+// narrow i32 there unpacks MOVL wwstage vs MOVQ cstage). The value always
+// fits i32 (cast at the init_dec_mant_exp call site). `mantissa` stays u32
+// (Hare's width); the {u32, pad, i64} layout's first eightbyte holds
+// mantissa@0 + 4B pad and reads cleanly — byte-id CONFIRMED by the 990-997
+// gate (0-diff cs vs ww), not relied on as an ABI guarantee.
+type decf32 = struct { mantissa: u32, exponent: i64 };
+
+// ref/hare/strconv/ftos_ryu.ha:392. Shortest decimal of an f32:
+// value == mantissa * 10^exponent. `mantissa`/`exponent` are the raw
+// IEEE-754 fields of an f32.
+fn f32todecf32(mantissa: u32, exponent: u32) decf32 = {
+	let e2: i32 = (math.F32_EXPONENT_BIAS + math.F32_MANTISSA_BITS + 2u32): i32;
+	let m2: u32 = 0u32;
+	if (exponent == 0u32) {
+		e2 = 1i32 - e2;
+		m2 = mantissa;
+	} else {
+		e2 = (exponent: i32) - e2;
+		m2 = (1u32 << math.F32_MANTISSA_BITS) | mantissa;
+	};
+	let accept_bounds: bool = (m2 & 1u32) == 0u32;
+	let mv: u32 = 4u32 * m2;
+	let mp: u32 = mv + 2u32;
+	let mm_shift: u32 = ibool(mantissa != 0u32 || exponent <= 1u32): u32;
+	let mm: u32 = mv - 1u32 - mm_shift;
+	let vr: u32 = 0u32;
+	let vp: u32 = 0u32;
+	let vm: u32 = 0u32;
+	let e10: i32 = 0i32;
+	let vm_trailing_zeroes: bool = false;
+	let vr_trailing_zeroes: bool = false;
+	let last_removed_digit: u8 = 0u8;
+	if (e2 >= 0i32) {
+		let q: u32 = log10pow2(e2: u32);
+		e10 = q: i32;
+		let k: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q) - 1u32;
+		let i: i32 = -e2 + ((q + k): i32);
+		vr = mulpow5inv_divpow2(mv, q, i);
+		vp = mulpow5inv_divpow2(mp, q, i);
+		vm = mulpow5inv_divpow2(mm, q, i);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			let l: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q - 1u32) - 1u32;
+			// #168 dodge: div/mod on an inline N_CALL result emits a
+			// signed IDIVQ in wwstage; bind the call to a local first.
+			let lrd: u32 = mulpow5inv_divpow2(mv, q - 1u32,
+				-e2 + ((q + l): i32) - 1i32);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 9u32) {
+			if (mv % 5u32 == 0u32) {
+				vr_trailing_zeroes = pow5multiple32(mv, q);
+			} else if (accept_bounds) {
+				vm_trailing_zeroes = pow5multiple32(mm, q);
+			} else {
+				vp -= (ibool(pow5multiple32(mp, q)): u32);
+			};
+		};
+	} else {
+		let q: u32 = log10pow5((-e2): u32);
+		e10 = (q: i32) + e2;
+		let i: u32 = (-e2 - (q: i32)): u32;
+		let k: u32 = pow5bits(i) - (F32_POW5_BITCOUNT: u32);
+		let j: i32 = (q: i32) - (k: i32);
+		vr = mulpow5_divpow2(mv, i, j);
+		vp = mulpow5_divpow2(mp, i, j);
+		vm = mulpow5_divpow2(mm, i, j);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			j = (q: i32) - 1i32 - ((pow5bits(i + 1u32): i32) - (F32_POW5_BITCOUNT: i32));
+			// #168 dodge (see above): local-bind before the % 10.
+			let lrd: u32 = mulpow5_divpow2(mv, (i + 1u32), j);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 1u32) {
+			vr_trailing_zeroes = true;
+			if (accept_bounds) {
+				vm_trailing_zeroes = mm_shift == 1u32;
+			} else {
+				vp -= 1u32;
+			};
+		} else if (q < 31u32) {
+			vr_trailing_zeroes = pow2multiple32(mv, q - 1u32);
+		};
+	};
+	let removed: i32 = 0i32;
+	let output: u32 = 0u32;
+	if (vm_trailing_zeroes || vr_trailing_zeroes) {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			vm_trailing_zeroes = vm_trailing_zeroes && ((vm - (vm / 10u32) * 10u32) == 0u32);
+			vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		if (vm_trailing_zeroes) {
+			for ((vm % 10u32) == 0u32) {
+				vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+				last_removed_digit = (vr % 10u32): u8;
+				vr /= 10u32;
+				vp /= 10u32;
+				vm /= 10u32;
+				removed += 1i32;
+			};
+		};
+		if (vr_trailing_zeroes && last_removed_digit == 5u8 && vr % 2u32 == 0u32) {
+			last_removed_digit = 4u8;	// round to even
+		};
+		let cond1: bool = (vr == vm) && ((!accept_bounds) || (!vm_trailing_zeroes));
+		let cond2: bool = last_removed_digit >= 5u8;
+		output = vr + (ibool(cond1 || cond2): u32);
+	} else {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		output = vr + (ibool(vr == vm || last_removed_digit >= 5u8): u32);
+	};
+	let exp: i32 = e10 + removed;
+	return decf32 { mantissa = output, exponent = (exp: i64) };
+};
+
 // ==== G-format encode layer (ftos.ha) — only the ffmt::G / prec=void /
 // fflags::NONE-REACHABLE logic. The SHOW_POINT/precision/E-vs-uppercase
 // arms (ftos.ha:88-105, 127-145, 170-213's zeros/caps) are UNREACHABLE
@@ -547,3 +735,64 @@ export fn f64tos(n: f64) str = {
 	r.len = o;
 	return r;
 };
+
+// ref/hare/strconv/ftos.ha:448. f32 → shortest base-10 str. Same static-
+// buffer convention + G/void/NONE-inlined path as f64tos. f32bits(n)
+// passes an f32 arg → MOVSS both stages post-#143 (aff7725); this is the
+// piece fold-5b was gated on.
+//
+// Hare sizes this [14]u8 (ftos.ha:451: 1 + 1 + 1 + 7 + 1 + 1 + 2). Sized
+// 32 to reuse f64tos's proven byte-id-clean band: a no-rhs [N]u8 module
+// buffer at the size-16/24 band emits divergent DATAW counts cs≠ww (#43);
+// 32 emits 2 DATAW in both. The unused tail bytes are harmless.
+let f32tos_buf: [32]u8;
+
+export fn f32tos(n: f32) str = {
+	let bits: u32 = math.f32bits(n);
+	let mantissa: u32 = bits & math.F32_MANTISSA_MASK;
+	let exponent: u32 = (bits >> math.F32_MANTISSA_BITS) & math.F32_EXPONENT_MASK;
+	let sign: bool = (bits >> (math.F32_EXPONENT_BITS + math.F32_MANTISSA_BITS)) > 0u32;
+	let special: bool = exponent == math.F32_EXPONENT_MASK;
+
+	let o: i32 = 0i32;
+	let r: str;
+	r.ptr = &f32tos_buf[0];
+	// NaN carries no sign prefix (ftos.ha:331-333, before sign handling).
+	if (special && mantissa != 0u32) {
+		o = putstr(f32tos_buf[0:32], o, "nan");
+		r.len = o;
+		return r;
+	};
+	if (sign) {
+		f32tos_buf[o] = 45u8;	// '-'
+		o += 1i32;
+	};
+	if (special) {
+		o = putstr(f32tos_buf[0:32], o, "infinity");
+		r.len = o;
+		return r;
+	};
+	if (exponent == 0u32 && mantissa == 0u32) {
+		f32tos_buf[o] = 48u8;	// '0' (encode_zero, G/void/NONE)
+		o += 1i32;
+		r.len = o;
+		return r;
+	};
+
+	let d = decimal { ... };
+	// *decimal pointer for the field reads (the #170 dodge; see f64tos).
+	let pd: *decimal = &d;
+	let dd: decf32 = f32todecf32(mantissa, exponent);
+	init_dec_mant_exp(pd, (dd.mantissa: u64), (dd.exponent: i32));
+	trim(pd);
+	if (pd.nd == (0u64: size)) {
+		f32tos_buf[o] = 48u8;	// rounded to zero
+		o += 1i32;
+	} else if (pd.dp < -1i32 || (pd.dp - (pd.nd: i32)) > 2i32) {
+		o = encode_e_dec(pd, f32tos_buf[0:32], o);
+	} else {
+		o = encode_f_dec(pd, f32tos_buf[0:32], o);
+	};
+	r.len = o;
+	return r;
+};
diff --git a/lib/strconv/ftos_data.ww b/lib/strconv/ftos_data.ww
index 0b9a90bb..c989f0b2 100644
--- a/lib/strconv/ftos_data.ww
+++ b/lib/strconv/ftos_data.ww
@@ -25,12 +25,18 @@ package strconv;
 // power-of-five tables. Defined u8 (faithful); ftos.ww casts to u32/i32
 // at each use site (Hare promotes a u8 def inside mixed-width arithmetic;
 // ww is strict — explicit cast, project_int_machine_word_derived_limits).
-// The F32_POW5_*_BITCOUNT siblings (ftos_ryu.ha:162-163) land in fold-5b
-// (task #67) with their only consumer, f32todecf32 — omitted here to keep
-// this fold dead-code-free.
 def F64_POW5_INV_BITCOUNT: u8 = 125u8;
 def F64_POW5_BITCOUNT: u8 = 125u8;
 
+// ref/hare/strconv/ftos_ryu.ha:162-163. The f32 split-table bit-counts,
+// derived from the f64 siblings (Hare: F64_..._BITCOUNT - 64). Consumed by
+// f32todecf32 (ftos.ww), landed in fold-5b (task #67) — the f32 path reuses
+// the f64 SPLIT2 tables (via f64computeinvpow5/f64computepow5), so no
+// separate F32 tables exist (matches ftos_ryu.ha). u8 like the f64 defs;
+// ftos.ww casts to u32/i32 at each use.
+def F32_POW5_INV_BITCOUNT: u8 = F64_POW5_INV_BITCOUNT - 64u8;
+def F32_POW5_BITCOUNT: u8 = F64_POW5_BITCOUNT - 64u8;
+
 // ref/hare/strconv/ftos_ryu.ha:165-181.
 let F64_POW5_INV_SPLIT2: [15][2]u64 = [
 	[1u64, 2305843009213693952u64],
diff --git a/lib/strconv/test/ftostest.ww b/lib/strconv/test/ftostest.ww
index 0b96f725..a89c9f86 100644
--- a/lib/strconv/test/ftostest.ww
+++ b/lib/strconv/test/ftostest.ww
@@ -10,8 +10,11 @@
 // math.f64frombits of the IEEE bit patterns (ww math has no f64 NAN/INF
 // const — see math/floats.ww).
 //
-// f32tos is NOT exercised here: it is deferred to fold-5b (task #67),
-// gated on the #143 f32-arg-push cs≠ww cgen fix.
+// f32tos (fold-5b, task #67) is exercised by f32tos_fixed/_scientific/
+// _extremes/_special below. The G/void rows mirror ftos_test.ha's tcs (the
+// "pass for both f32 and f64" set, lines 9/183); the _extremes rows mirror
+// tcsf32 (ftos_test.ha:218-221, the f32-EXCLUSIVE denormal/min/max — full
+// f32 mantissa). f32 values use the `f32` literal suffix or f32frombits.
 //
 // Lives in lib/strconv/test/ so `import strconv` resolves to the
 // DIRECTORY (full package), not the strconv.ww FILE — same rationale as
@@ -84,10 +87,78 @@ fn chk(n: f64, want: str) bool = {
 	if (!chk(nan, "nan")) { fail(); };
 };
 
+fn chkf32(n: f32, want: str) bool = {
+	return streq(f32tos(n), want);
+};
+
+// ftos_test.ha tcs G/void rows (the "pass for both f32 and f64" set) —
+// fixed-point renders. 1.0/1.5/0.1/100/0.5 are the fold-5a probe's 5/5
+// value-validated f32todecf32 pairs.
+@test fn f32tos_fixed() void = {
+	if (!chkf32(13.37f32, "13.37")) { fail(); };
+	if (!chkf32(-13.37f32, "-13.37")) { fail(); };	// sign prefix + encode_f at o=1
+	// 2^25: the smallest f32 with e2 >= 0 (q == 0) — the ONLY runtime cover
+	// of f32todecf32's e2>=0 / q<=9 trailing-zero block (the f32-specific
+	// `q <= 9` + pow5multiple32 arm). External shortest-round-trip check.
+	if (!chkf32(33554432.0f32, "33554432")) { fail(); };
+	if (!chkf32(12345.0f32, "12345")) { fail(); };
+	if (!chkf32(1100.0f32, "1100")) { fail(); };
+	if (!chkf32(100.0f32, "100")) { fail(); };
+	if (!chkf32(10.0f32, "10")) { fail(); };
+	if (!chkf32(1.0f32, "1")) { fail(); };
+	if (!chkf32(1.5f32, "1.5")) { fail(); };
+	if (!chkf32(0.5f32, "0.5")) { fail(); };
+	if (!chkf32(0.1f32, "0.1")) { fail(); };
+	if (!chkf32(0.01f32, "0.01")) { fail(); };
+	if (!chkf32(0.011f32, "0.011")) { fail(); };
+};
+
+// ftos_test.ha tcs G/void rows — scientific (shortest-G E-dispatch).
+@test fn f32tos_scientific() void = {
+	if (!chkf32(10000.0f32, "1e4")) { fail(); };
+	if (!chkf32(11000.0f32, "1.1e4")) { fail(); };
+	if (!chkf32(1000.0f32, "1e3")) { fail(); };
+	if (!chkf32(0.001f32, "1e-3")) { fail(); };
+	if (!chkf32(0.0011f32, "1.1e-3")) { fail(); };
+	if (!chkf32(0.0001f32, "1e-4")) { fail(); };
+};
+
+// ftos_test.ha:218-221 (tcsf32) — the f32-EXCLUSIVE denormal/min-normal/
+// max-normal rows (distinct outputs from f64): exercise the full f32
+// mantissa (8 sig digits) + 2-digit exponent. Built via f32frombits of the
+// IEEE-754 bit patterns (ww math has no F32_MIN_*/MAX_NORMAL const).
+@test fn f32tos_extremes() void = {
+	let minsub: f32 = math.f32frombits(1u32);	// 2^-149
+	if (!chkf32(minsub, "1e-45")) { fail(); };
+	let minnorm: f32 = math.f32frombits(0x00800000u32);	// 2^-126
+	if (!chkf32(minnorm, "1.1754944e-38")) { fail(); };
+	let maxnorm: f32 = math.f32frombits(0x7F7FFFFFu32);
+	if (!chkf32(maxnorm, "3.4028235e38")) { fail(); };
+};
+
+// ftos_test.ha:11/15/26 — zero, ±infinity, nan (f32 bit patterns).
+@test fn f32tos_special() void = {
+	if (!chkf32(0.0f32, "0")) { fail(); };
+	// sign bit via (1u32 << 31), mirroring the f64 test's I64_MIN-literal
+	// avoidance (#144 family).
+	let negzero: f32 = math.f32frombits(1u32 << 31u32);
+	if (!chkf32(negzero, "-0")) { fail(); };
+	let inf: f32 = math.f32frombits(0x7F800000u32);
+	if (!chkf32(inf, "infinity")) { fail(); };
+	let ninf: f32 = math.f32frombits(0xFF800000u32);
+	if (!chkf32(ninf, "-infinity")) { fail(); };
+	let nan: f32 = math.f32frombits(0x7FC00000u32);
+	if (!chkf32(nan, "nan")) { fail(); };
+};
+
 export fn main() i32 = {
 	signalled = 1; f64tos_fixed();
 	signalled = 2; f64tos_scientific();
 	signalled = 3; f64tos_special();
+	signalled = 4; f32tos_fixed();
+	signalled = 5; f32tos_scientific();
+	signalled = 6; f32tos_extremes();
+	signalled = 7; f32tos_special();
 	os.exit(0);
 	return 0;
 };
diff --git a/selfhost/cmd/w6c/main.combined.ww b/selfhost/cmd/w6c/main.combined.ww
index e1f20a5a..5bca2514 100644
--- a/selfhost/cmd/w6c/main.combined.ww
+++ b/selfhost/cmd/w6c/main.combined.ww
@@ -3322,15 +3322,14 @@ export fn absi64(n: i64) u64 = {
 // https://doi.org/10.1145/3192366.3192369 — Hare translated it from the
 // reference C (https://github.com/ulfjack/ryu); ww follows Hare.
 //
-// SCOPE — the f64tos shortest-representation subset (Hare's ffmt::G,
-// prec=void, fflags::NONE). Two deferrals:
-//   - f32tos (ftos.ha:448) + its f32 Ryū sub-path (f32todecf32 +
-//     mulpow5inv/pow5_divpow2 + mulshift32 + the *32 helpers + the
-//     F32_POW5_*_BITCOUNT defs) → fold-5b (task #67), gated on the #143
-//     f32-arg-push cgen fix: f32tos must call math.f32bits(n), passing
-//     an f32 arg, which spills MOVSD (cstage) vs MOVSS (wwstage) →
-//     990-997 byte-id break. Not isolatable (f32bits IS the reinterpret),
-//     only fixable. f32tos IS a real Hare entry — it ships in #67.
+// SCOPE — the f64tos + f32tos shortest-representation subset (Hare's
+// ffmt::G, prec=void, fflags::NONE). f32tos (ftos.ha:448) + its f32 Ryū
+// sub-path (f32todecf32 + mulpow5inv/pow5_divpow2 + mulshift32 + the *32
+// helpers, reusing the shared u64-core + the f64 SPLIT2 tables — the f32
+// path has no separate tables, matching ftos_ryu.ha) ship here in fold-5b
+// (task #67): the gating #143 f32-arg-push cgen fix landed (aff7725, MOVSS
+// both stages), so f32tos's math.f32bits(n) call — passing an f32 arg — is
+// now byte-id-clean. One deferral remains:
 //   - the parametric fftosf/ffmt/fflags/ftosf surface → task #64 (needs
 //     io::handle/memio + a `(size|io::error)?` per appendrune (#158);
 //     for G/void/NONE the ffmt/fflags/precision/multiprecision-fallback
@@ -3658,6 +3657,195 @@ fn f64todecf64(mantissa: u64, exponent: u32) decf64 = {
 	return decf64 { exponent = (exp: i64), mantissa = output };
 };
 
+// ==== f32 Ryū sub-path (ftos_ryu.ha). The *32 helpers below mirror their
+// u64 siblings at 32-bit width; they reuse the SHARED f64computeinvpow5/
+// f64computepow5 (and thus the f64 SPLIT2 tables) per ftos_ryu.ha — there
+// is no separate f32 table. Same scalar-PARAM-mutation → copy-to-local,
+// comma-split, assert → os.assert, expr-yield → block divergences as the
+// f64 path above. ====
+
+// ref/hare/strconv/ftos_ryu.ha:52. Largest p with 5^p | value (32-bit).
+fn pow5fac32(v: u32) u32 = {
+	let value: u32 = v;
+	let count: u32 = 0u32;
+	for (true) {
+		os.assert(value != 0u32, "strconv.pow5fac32: value == 0");
+		let q: u32 = value / 5u32;
+		let r: u32 = value % 5u32;
+		if (r != 0u32) { break; };
+		value = q;
+		count += 1u32;
+	};
+	return count;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:67.
+fn pow5multiple32(v: u32, p: u32) bool = { return pow5fac32(v) >= p; };
+
+// ref/hare/strconv/ftos_ryu.ha:75.
+fn pow2multiple32(v: u32, p: u32) bool = {
+	os.assert(v > 0u32, "strconv.pow2multiple32: v == 0");
+	os.assert(p < 32u32, "strconv.pow2multiple32: p >= 32");
+	return (v & ((1u32 << p) - 1u32)) == 0u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:121. `m * a_lo` etc. carry an explicit
+// (m: u64) cast (Hare promotes the u32 operand; ww is strict). The bound
+// assert inlines U32_MAX's value: ww's types.U32_MAX is package-private
+// (lib/types/types.ww — no `export`), so Hare's `types::U32_MAX` can't be
+// referenced cross-package.
+fn mulshift32(m: u32, a: u64, s: u32) u32 = {
+	os.assert(s > 32u32, "strconv.mulshift32: s <= 32");
+	let a_lo: u64 = (a: u32): u64;
+	let a_hi: u64 = a >> 32u64;
+	let b0: u64 = (m: u64) * a_lo;
+	let b1: u64 = (m: u64) * a_hi;
+	let sum: u64 = (b0 >> 32u64) + b1;
+	let ss: u64 = sum >> ((s: u64) - 32u64);
+	os.assert(ss <= 4294967295u64, "strconv.mulshift32: ss > U32_MAX");
+	return ss: u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:130.
+fn mulpow5inv_divpow2(m: u32, q: u32, j: i32) u32 = {
+	let pow5 = f64computeinvpow5(q);
+	return mulshift32(m, pow5.1 + 1u64, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:135.
+fn mulpow5_divpow2(m: u32, i: u32, j: i32) u32 = {
+	let pow5 = f64computepow5(i);
+	return mulshift32(m, pow5.1, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:387. `exponent` rides i64 not Hare's i32,
+// for the same reason decf64 does: widening the field to a full second
+// eightbyte SIDESTEPS the #169 narrow-i32-field struct-return unpack (a
+// narrow i32 there unpacks MOVL wwstage vs MOVQ cstage). The value always
+// fits i32 (cast at the init_dec_mant_exp call site). `mantissa` stays u32
+// (Hare's width); the {u32, pad, i64} layout's first eightbyte holds
+// mantissa@0 + 4B pad and reads cleanly — byte-id CONFIRMED by the 990-997
+// gate (0-diff cs vs ww), not relied on as an ABI guarantee.
+type decf32 = struct { mantissa: u32, exponent: i64 };
+
+// ref/hare/strconv/ftos_ryu.ha:392. Shortest decimal of an f32:
+// value == mantissa * 10^exponent. `mantissa`/`exponent` are the raw
+// IEEE-754 fields of an f32.
+fn f32todecf32(mantissa: u32, exponent: u32) decf32 = {
+	let e2: i32 = (math.F32_EXPONENT_BIAS + math.F32_MANTISSA_BITS + 2u32): i32;
+	let m2: u32 = 0u32;
+	if (exponent == 0u32) {
+		e2 = 1i32 - e2;
+		m2 = mantissa;
+	} else {
+		e2 = (exponent: i32) - e2;
+		m2 = (1u32 << math.F32_MANTISSA_BITS) | mantissa;
+	};
+	let accept_bounds: bool = (m2 & 1u32) == 0u32;
+	let mv: u32 = 4u32 * m2;
+	let mp: u32 = mv + 2u32;
+	let mm_shift: u32 = ibool(mantissa != 0u32 || exponent <= 1u32): u32;
+	let mm: u32 = mv - 1u32 - mm_shift;
+	let vr: u32 = 0u32;
+	let vp: u32 = 0u32;
+	let vm: u32 = 0u32;
+	let e10: i32 = 0i32;
+	let vm_trailing_zeroes: bool = false;
+	let vr_trailing_zeroes: bool = false;
+	let last_removed_digit: u8 = 0u8;
+	if (e2 >= 0i32) {
+		let q: u32 = log10pow2(e2: u32);
+		e10 = q: i32;
+		let k: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q) - 1u32;
+		let i: i32 = -e2 + ((q + k): i32);
+		vr = mulpow5inv_divpow2(mv, q, i);
+		vp = mulpow5inv_divpow2(mp, q, i);
+		vm = mulpow5inv_divpow2(mm, q, i);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			let l: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q - 1u32) - 1u32;
+			// #168 dodge: div/mod on an inline N_CALL result emits a
+			// signed IDIVQ in wwstage; bind the call to a local first.
+			let lrd: u32 = mulpow5inv_divpow2(mv, q - 1u32,
+				-e2 + ((q + l): i32) - 1i32);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 9u32) {
+			if (mv % 5u32 == 0u32) {
+				vr_trailing_zeroes = pow5multiple32(mv, q);
+			} else if (accept_bounds) {
+				vm_trailing_zeroes = pow5multiple32(mm, q);
+			} else {
+				vp -= (ibool(pow5multiple32(mp, q)): u32);
+			};
+		};
+	} else {
+		let q: u32 = log10pow5((-e2): u32);
+		e10 = (q: i32) + e2;
+		let i: u32 = (-e2 - (q: i32)): u32;
+		let k: u32 = pow5bits(i) - (F32_POW5_BITCOUNT: u32);
+		let j: i32 = (q: i32) - (k: i32);
+		vr = mulpow5_divpow2(mv, i, j);
+		vp = mulpow5_divpow2(mp, i, j);
+		vm = mulpow5_divpow2(mm, i, j);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			j = (q: i32) - 1i32 - ((pow5bits(i + 1u32): i32) - (F32_POW5_BITCOUNT: i32));
+			// #168 dodge (see above): local-bind before the % 10.
+			let lrd: u32 = mulpow5_divpow2(mv, (i + 1u32), j);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 1u32) {
+			vr_trailing_zeroes = true;
+			if (accept_bounds) {
+				vm_trailing_zeroes = mm_shift == 1u32;
+			} else {
+				vp -= 1u32;
+			};
+		} else if (q < 31u32) {
+			vr_trailing_zeroes = pow2multiple32(mv, q - 1u32);
+		};
+	};
+	let removed: i32 = 0i32;
+	let output: u32 = 0u32;
+	if (vm_trailing_zeroes || vr_trailing_zeroes) {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			vm_trailing_zeroes = vm_trailing_zeroes && ((vm - (vm / 10u32) * 10u32) == 0u32);
+			vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		if (vm_trailing_zeroes) {
+			for ((vm % 10u32) == 0u32) {
+				vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+				last_removed_digit = (vr % 10u32): u8;
+				vr /= 10u32;
+				vp /= 10u32;
+				vm /= 10u32;
+				removed += 1i32;
+			};
+		};
+		if (vr_trailing_zeroes && last_removed_digit == 5u8 && vr % 2u32 == 0u32) {
+			last_removed_digit = 4u8;	// round to even
+		};
+		let cond1: bool = (vr == vm) && ((!accept_bounds) || (!vm_trailing_zeroes));
+		let cond2: bool = last_removed_digit >= 5u8;
+		output = vr + (ibool(cond1 || cond2): u32);
+	} else {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		output = vr + (ibool(vr == vm || last_removed_digit >= 5u8): u32);
+	};
+	let exp: i32 = e10 + removed;
+	return decf32 { mantissa = output, exponent = (exp: i64) };
+};
+
 // ==== G-format encode layer (ftos.ha) — only the ffmt::G / prec=void /
 // fflags::NONE-REACHABLE logic. The SHOW_POINT/precision/E-vs-uppercase
 // arms (ftos.ha:88-105, 127-145, 170-213's zeros/caps) are UNREACHABLE
@@ -3866,6 +4054,67 @@ export fn f64tos(n: f64) str = {
 	return r;
 };
 
+// ref/hare/strconv/ftos.ha:448. f32 → shortest base-10 str. Same static-
+// buffer convention + G/void/NONE-inlined path as f64tos. f32bits(n)
+// passes an f32 arg → MOVSS both stages post-#143 (aff7725); this is the
+// piece fold-5b was gated on.
+//
+// Hare sizes this [14]u8 (ftos.ha:451: 1 + 1 + 1 + 7 + 1 + 1 + 2). Sized
+// 32 to reuse f64tos's proven byte-id-clean band: a no-rhs [N]u8 module
+// buffer at the size-16/24 band emits divergent DATAW counts cs≠ww (#43);
+// 32 emits 2 DATAW in both. The unused tail bytes are harmless.
+let f32tos_buf: [32]u8;
+
+export fn f32tos(n: f32) str = {
+	let bits: u32 = math.f32bits(n);
+	let mantissa: u32 = bits & math.F32_MANTISSA_MASK;
+	let exponent: u32 = (bits >> math.F32_MANTISSA_BITS) & math.F32_EXPONENT_MASK;
+	let sign: bool = (bits >> (math.F32_EXPONENT_BITS + math.F32_MANTISSA_BITS)) > 0u32;
+	let special: bool = exponent == math.F32_EXPONENT_MASK;
+
+	let o: i32 = 0i32;
+	let r: str;
+	r.ptr = &f32tos_buf[0];
+	// NaN carries no sign prefix (ftos.ha:331-333, before sign handling).
+	if (special && mantissa != 0u32) {
+		o = putstr(f32tos_buf[0:32], o, "nan");
+		r.len = o;
+		return r;
+	};
+	if (sign) {
+		f32tos_buf[o] = 45u8;	// '-'
+		o += 1i32;
+	};
+	if (special) {
+		o = putstr(f32tos_buf[0:32], o, "infinity");
+		r.len = o;
+		return r;
+	};
+	if (exponent == 0u32 && mantissa == 0u32) {
+		f32tos_buf[o] = 48u8;	// '0' (encode_zero, G/void/NONE)
+		o += 1i32;
+		r.len = o;
+		return r;
+	};
+
+	let d = decimal { ... };
+	// *decimal pointer for the field reads (the #170 dodge; see f64tos).
+	let pd: *decimal = &d;
+	let dd: decf32 = f32todecf32(mantissa, exponent);
+	init_dec_mant_exp(pd, (dd.mantissa: u64), (dd.exponent: i32));
+	trim(pd);
+	if (pd.nd == (0u64: size)) {
+		f32tos_buf[o] = 48u8;	// rounded to zero
+		o += 1i32;
+	} else if (pd.dp < -1i32 || (pd.dp - (pd.nd: i32)) > 2i32) {
+		o = encode_e_dec(pd, f32tos_buf[0:32], o);
+	} else {
+		o = encode_f_dec(pd, f32tos_buf[0:32], o);
+	};
+	r.len = o;
+	return r;
+};
+
 // strconv — Ryū float→string lookup tables + bit-count constants.
 // Mirrors ref/hare/strconv/ftos_ryu.ha:159-222 byte-exact. Pure data
 // fold (strconv #106 fold-5): no logic, consumed by ftos.ww's
@@ -3893,12 +4142,18 @@ package strconv;
 // power-of-five tables. Defined u8 (faithful); ftos.ww casts to u32/i32
 // at each use site (Hare promotes a u8 def inside mixed-width arithmetic;
 // ww is strict — explicit cast, project_int_machine_word_derived_limits).
-// The F32_POW5_*_BITCOUNT siblings (ftos_ryu.ha:162-163) land in fold-5b
-// (task #67) with their only consumer, f32todecf32 — omitted here to keep
-// this fold dead-code-free.
 def F64_POW5_INV_BITCOUNT: u8 = 125u8;
 def F64_POW5_BITCOUNT: u8 = 125u8;
 
+// ref/hare/strconv/ftos_ryu.ha:162-163. The f32 split-table bit-counts,
+// derived from the f64 siblings (Hare: F64_..._BITCOUNT - 64). Consumed by
+// f32todecf32 (ftos.ww), landed in fold-5b (task #67) — the f32 path reuses
+// the f64 SPLIT2 tables (via f64computeinvpow5/f64computepow5), so no
+// separate F32 tables exist (matches ftos_ryu.ha). u8 like the f64 defs;
+// ftos.ww casts to u32/i32 at each use.
+def F32_POW5_INV_BITCOUNT: u8 = F64_POW5_INV_BITCOUNT - 64u8;
+def F32_POW5_BITCOUNT: u8 = F64_POW5_BITCOUNT - 64u8;
+
 // ref/hare/strconv/ftos_ryu.ha:165-181.
 let F64_POW5_INV_SPLIT2: [15][2]u64 = [
 	[1u64, 2305843009213693952u64],
diff --git a/selfhost/cmd/wwdump/main.combined.ww b/selfhost/cmd/wwdump/main.combined.ww
index 1407ee29..70493e59 100644
--- a/selfhost/cmd/wwdump/main.combined.ww
+++ b/selfhost/cmd/wwdump/main.combined.ww
@@ -1345,15 +1345,14 @@ export fn absi64(n: i64) u64 = {
 // https://doi.org/10.1145/3192366.3192369 — Hare translated it from the
 // reference C (https://github.com/ulfjack/ryu); ww follows Hare.
 //
-// SCOPE — the f64tos shortest-representation subset (Hare's ffmt::G,
-// prec=void, fflags::NONE). Two deferrals:
-//   - f32tos (ftos.ha:448) + its f32 Ryū sub-path (f32todecf32 +
-//     mulpow5inv/pow5_divpow2 + mulshift32 + the *32 helpers + the
-//     F32_POW5_*_BITCOUNT defs) → fold-5b (task #67), gated on the #143
-//     f32-arg-push cgen fix: f32tos must call math.f32bits(n), passing
-//     an f32 arg, which spills MOVSD (cstage) vs MOVSS (wwstage) →
-//     990-997 byte-id break. Not isolatable (f32bits IS the reinterpret),
-//     only fixable. f32tos IS a real Hare entry — it ships in #67.
+// SCOPE — the f64tos + f32tos shortest-representation subset (Hare's
+// ffmt::G, prec=void, fflags::NONE). f32tos (ftos.ha:448) + its f32 Ryū
+// sub-path (f32todecf32 + mulpow5inv/pow5_divpow2 + mulshift32 + the *32
+// helpers, reusing the shared u64-core + the f64 SPLIT2 tables — the f32
+// path has no separate tables, matching ftos_ryu.ha) ship here in fold-5b
+// (task #67): the gating #143 f32-arg-push cgen fix landed (aff7725, MOVSS
+// both stages), so f32tos's math.f32bits(n) call — passing an f32 arg — is
+// now byte-id-clean. One deferral remains:
 //   - the parametric fftosf/ffmt/fflags/ftosf surface → task #64 (needs
 //     io::handle/memio + a `(size|io::error)?` per appendrune (#158);
 //     for G/void/NONE the ffmt/fflags/precision/multiprecision-fallback
@@ -1681,6 +1680,195 @@ fn f64todecf64(mantissa: u64, exponent: u32) decf64 = {
 	return decf64 { exponent = (exp: i64), mantissa = output };
 };
 
+// ==== f32 Ryū sub-path (ftos_ryu.ha). The *32 helpers below mirror their
+// u64 siblings at 32-bit width; they reuse the SHARED f64computeinvpow5/
+// f64computepow5 (and thus the f64 SPLIT2 tables) per ftos_ryu.ha — there
+// is no separate f32 table. Same scalar-PARAM-mutation → copy-to-local,
+// comma-split, assert → os.assert, expr-yield → block divergences as the
+// f64 path above. ====
+
+// ref/hare/strconv/ftos_ryu.ha:52. Largest p with 5^p | value (32-bit).
+fn pow5fac32(v: u32) u32 = {
+	let value: u32 = v;
+	let count: u32 = 0u32;
+	for (true) {
+		os.assert(value != 0u32, "strconv.pow5fac32: value == 0");
+		let q: u32 = value / 5u32;
+		let r: u32 = value % 5u32;
+		if (r != 0u32) { break; };
+		value = q;
+		count += 1u32;
+	};
+	return count;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:67.
+fn pow5multiple32(v: u32, p: u32) bool = { return pow5fac32(v) >= p; };
+
+// ref/hare/strconv/ftos_ryu.ha:75.
+fn pow2multiple32(v: u32, p: u32) bool = {
+	os.assert(v > 0u32, "strconv.pow2multiple32: v == 0");
+	os.assert(p < 32u32, "strconv.pow2multiple32: p >= 32");
+	return (v & ((1u32 << p) - 1u32)) == 0u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:121. `m * a_lo` etc. carry an explicit
+// (m: u64) cast (Hare promotes the u32 operand; ww is strict). The bound
+// assert inlines U32_MAX's value: ww's types.U32_MAX is package-private
+// (lib/types/types.ww — no `export`), so Hare's `types::U32_MAX` can't be
+// referenced cross-package.
+fn mulshift32(m: u32, a: u64, s: u32) u32 = {
+	os.assert(s > 32u32, "strconv.mulshift32: s <= 32");
+	let a_lo: u64 = (a: u32): u64;
+	let a_hi: u64 = a >> 32u64;
+	let b0: u64 = (m: u64) * a_lo;
+	let b1: u64 = (m: u64) * a_hi;
+	let sum: u64 = (b0 >> 32u64) + b1;
+	let ss: u64 = sum >> ((s: u64) - 32u64);
+	os.assert(ss <= 4294967295u64, "strconv.mulshift32: ss > U32_MAX");
+	return ss: u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:130.
+fn mulpow5inv_divpow2(m: u32, q: u32, j: i32) u32 = {
+	let pow5 = f64computeinvpow5(q);
+	return mulshift32(m, pow5.1 + 1u64, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:135.
+fn mulpow5_divpow2(m: u32, i: u32, j: i32) u32 = {
+	let pow5 = f64computepow5(i);
+	return mulshift32(m, pow5.1, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:387. `exponent` rides i64 not Hare's i32,
+// for the same reason decf64 does: widening the field to a full second
+// eightbyte SIDESTEPS the #169 narrow-i32-field struct-return unpack (a
+// narrow i32 there unpacks MOVL wwstage vs MOVQ cstage). The value always
+// fits i32 (cast at the init_dec_mant_exp call site). `mantissa` stays u32
+// (Hare's width); the {u32, pad, i64} layout's first eightbyte holds
+// mantissa@0 + 4B pad and reads cleanly — byte-id CONFIRMED by the 990-997
+// gate (0-diff cs vs ww), not relied on as an ABI guarantee.
+type decf32 = struct { mantissa: u32, exponent: i64 };
+
+// ref/hare/strconv/ftos_ryu.ha:392. Shortest decimal of an f32:
+// value == mantissa * 10^exponent. `mantissa`/`exponent` are the raw
+// IEEE-754 fields of an f32.
+fn f32todecf32(mantissa: u32, exponent: u32) decf32 = {
+	let e2: i32 = (math.F32_EXPONENT_BIAS + math.F32_MANTISSA_BITS + 2u32): i32;
+	let m2: u32 = 0u32;
+	if (exponent == 0u32) {
+		e2 = 1i32 - e2;
+		m2 = mantissa;
+	} else {
+		e2 = (exponent: i32) - e2;
+		m2 = (1u32 << math.F32_MANTISSA_BITS) | mantissa;
+	};
+	let accept_bounds: bool = (m2 & 1u32) == 0u32;
+	let mv: u32 = 4u32 * m2;
+	let mp: u32 = mv + 2u32;
+	let mm_shift: u32 = ibool(mantissa != 0u32 || exponent <= 1u32): u32;
+	let mm: u32 = mv - 1u32 - mm_shift;
+	let vr: u32 = 0u32;
+	let vp: u32 = 0u32;
+	let vm: u32 = 0u32;
+	let e10: i32 = 0i32;
+	let vm_trailing_zeroes: bool = false;
+	let vr_trailing_zeroes: bool = false;
+	let last_removed_digit: u8 = 0u8;
+	if (e2 >= 0i32) {
+		let q: u32 = log10pow2(e2: u32);
+		e10 = q: i32;
+		let k: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q) - 1u32;
+		let i: i32 = -e2 + ((q + k): i32);
+		vr = mulpow5inv_divpow2(mv, q, i);
+		vp = mulpow5inv_divpow2(mp, q, i);
+		vm = mulpow5inv_divpow2(mm, q, i);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			let l: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q - 1u32) - 1u32;
+			// #168 dodge: div/mod on an inline N_CALL result emits a
+			// signed IDIVQ in wwstage; bind the call to a local first.
+			let lrd: u32 = mulpow5inv_divpow2(mv, q - 1u32,
+				-e2 + ((q + l): i32) - 1i32);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 9u32) {
+			if (mv % 5u32 == 0u32) {
+				vr_trailing_zeroes = pow5multiple32(mv, q);
+			} else if (accept_bounds) {
+				vm_trailing_zeroes = pow5multiple32(mm, q);
+			} else {
+				vp -= (ibool(pow5multiple32(mp, q)): u32);
+			};
+		};
+	} else {
+		let q: u32 = log10pow5((-e2): u32);
+		e10 = (q: i32) + e2;
+		let i: u32 = (-e2 - (q: i32)): u32;
+		let k: u32 = pow5bits(i) - (F32_POW5_BITCOUNT: u32);
+		let j: i32 = (q: i32) - (k: i32);
+		vr = mulpow5_divpow2(mv, i, j);
+		vp = mulpow5_divpow2(mp, i, j);
+		vm = mulpow5_divpow2(mm, i, j);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			j = (q: i32) - 1i32 - ((pow5bits(i + 1u32): i32) - (F32_POW5_BITCOUNT: i32));
+			// #168 dodge (see above): local-bind before the % 10.
+			let lrd: u32 = mulpow5_divpow2(mv, (i + 1u32), j);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 1u32) {
+			vr_trailing_zeroes = true;
+			if (accept_bounds) {
+				vm_trailing_zeroes = mm_shift == 1u32;
+			} else {
+				vp -= 1u32;
+			};
+		} else if (q < 31u32) {
+			vr_trailing_zeroes = pow2multiple32(mv, q - 1u32);
+		};
+	};
+	let removed: i32 = 0i32;
+	let output: u32 = 0u32;
+	if (vm_trailing_zeroes || vr_trailing_zeroes) {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			vm_trailing_zeroes = vm_trailing_zeroes && ((vm - (vm / 10u32) * 10u32) == 0u32);
+			vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		if (vm_trailing_zeroes) {
+			for ((vm % 10u32) == 0u32) {
+				vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+				last_removed_digit = (vr % 10u32): u8;
+				vr /= 10u32;
+				vp /= 10u32;
+				vm /= 10u32;
+				removed += 1i32;
+			};
+		};
+		if (vr_trailing_zeroes && last_removed_digit == 5u8 && vr % 2u32 == 0u32) {
+			last_removed_digit = 4u8;	// round to even
+		};
+		let cond1: bool = (vr == vm) && ((!accept_bounds) || (!vm_trailing_zeroes));
+		let cond2: bool = last_removed_digit >= 5u8;
+		output = vr + (ibool(cond1 || cond2): u32);
+	} else {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		output = vr + (ibool(vr == vm || last_removed_digit >= 5u8): u32);
+	};
+	let exp: i32 = e10 + removed;
+	return decf32 { mantissa = output, exponent = (exp: i64) };
+};
+
 // ==== G-format encode layer (ftos.ha) — only the ffmt::G / prec=void /
 // fflags::NONE-REACHABLE logic. The SHOW_POINT/precision/E-vs-uppercase
 // arms (ftos.ha:88-105, 127-145, 170-213's zeros/caps) are UNREACHABLE
@@ -1889,6 +2077,67 @@ export fn f64tos(n: f64) str = {
 	return r;
 };
 
+// ref/hare/strconv/ftos.ha:448. f32 → shortest base-10 str. Same static-
+// buffer convention + G/void/NONE-inlined path as f64tos. f32bits(n)
+// passes an f32 arg → MOVSS both stages post-#143 (aff7725); this is the
+// piece fold-5b was gated on.
+//
+// Hare sizes this [14]u8 (ftos.ha:451: 1 + 1 + 1 + 7 + 1 + 1 + 2). Sized
+// 32 to reuse f64tos's proven byte-id-clean band: a no-rhs [N]u8 module
+// buffer at the size-16/24 band emits divergent DATAW counts cs≠ww (#43);
+// 32 emits 2 DATAW in both. The unused tail bytes are harmless.
+let f32tos_buf: [32]u8;
+
+export fn f32tos(n: f32) str = {
+	let bits: u32 = math.f32bits(n);
+	let mantissa: u32 = bits & math.F32_MANTISSA_MASK;
+	let exponent: u32 = (bits >> math.F32_MANTISSA_BITS) & math.F32_EXPONENT_MASK;
+	let sign: bool = (bits >> (math.F32_EXPONENT_BITS + math.F32_MANTISSA_BITS)) > 0u32;
+	let special: bool = exponent == math.F32_EXPONENT_MASK;
+
+	let o: i32 = 0i32;
+	let r: str;
+	r.ptr = &f32tos_buf[0];
+	// NaN carries no sign prefix (ftos.ha:331-333, before sign handling).
+	if (special && mantissa != 0u32) {
+		o = putstr(f32tos_buf[0:32], o, "nan");
+		r.len = o;
+		return r;
+	};
+	if (sign) {
+		f32tos_buf[o] = 45u8;	// '-'
+		o += 1i32;
+	};
+	if (special) {
+		o = putstr(f32tos_buf[0:32], o, "infinity");
+		r.len = o;
+		return r;
+	};
+	if (exponent == 0u32 && mantissa == 0u32) {
+		f32tos_buf[o] = 48u8;	// '0' (encode_zero, G/void/NONE)
+		o += 1i32;
+		r.len = o;
+		return r;
+	};
+
+	let d = decimal { ... };
+	// *decimal pointer for the field reads (the #170 dodge; see f64tos).
+	let pd: *decimal = &d;
+	let dd: decf32 = f32todecf32(mantissa, exponent);
+	init_dec_mant_exp(pd, (dd.mantissa: u64), (dd.exponent: i32));
+	trim(pd);
+	if (pd.nd == (0u64: size)) {
+		f32tos_buf[o] = 48u8;	// rounded to zero
+		o += 1i32;
+	} else if (pd.dp < -1i32 || (pd.dp - (pd.nd: i32)) > 2i32) {
+		o = encode_e_dec(pd, f32tos_buf[0:32], o);
+	} else {
+		o = encode_f_dec(pd, f32tos_buf[0:32], o);
+	};
+	r.len = o;
+	return r;
+};
+
 // strconv — Ryū float→string lookup tables + bit-count constants.
 // Mirrors ref/hare/strconv/ftos_ryu.ha:159-222 byte-exact. Pure data
 // fold (strconv #106 fold-5): no logic, consumed by ftos.ww's
@@ -1916,12 +2165,18 @@ package strconv;
 // power-of-five tables. Defined u8 (faithful); ftos.ww casts to u32/i32
 // at each use site (Hare promotes a u8 def inside mixed-width arithmetic;
 // ww is strict — explicit cast, project_int_machine_word_derived_limits).
-// The F32_POW5_*_BITCOUNT siblings (ftos_ryu.ha:162-163) land in fold-5b
-// (task #67) with their only consumer, f32todecf32 — omitted here to keep
-// this fold dead-code-free.
 def F64_POW5_INV_BITCOUNT: u8 = 125u8;
 def F64_POW5_BITCOUNT: u8 = 125u8;
 
+// ref/hare/strconv/ftos_ryu.ha:162-163. The f32 split-table bit-counts,
+// derived from the f64 siblings (Hare: F64_..._BITCOUNT - 64). Consumed by
+// f32todecf32 (ftos.ww), landed in fold-5b (task #67) — the f32 path reuses
+// the f64 SPLIT2 tables (via f64computeinvpow5/f64computepow5), so no
+// separate F32 tables exist (matches ftos_ryu.ha). u8 like the f64 defs;
+// ftos.ww casts to u32/i32 at each use.
+def F32_POW5_INV_BITCOUNT: u8 = F64_POW5_INV_BITCOUNT - 64u8;
+def F32_POW5_BITCOUNT: u8 = F64_POW5_BITCOUNT - 64u8;
+
 // ref/hare/strconv/ftos_ryu.ha:165-181.
 let F64_POW5_INV_SPLIT2: [15][2]u64 = [
 	[1u64, 2305843009213693952u64],
diff --git a/selfhost/test/smoke.combined.ww b/selfhost/test/smoke.combined.ww
index 7863f99b..6d302631 100644
--- a/selfhost/test/smoke.combined.ww
+++ b/selfhost/test/smoke.combined.ww
@@ -1345,15 +1345,14 @@ export fn absi64(n: i64) u64 = {
 // https://doi.org/10.1145/3192366.3192369 — Hare translated it from the
 // reference C (https://github.com/ulfjack/ryu); ww follows Hare.
 //
-// SCOPE — the f64tos shortest-representation subset (Hare's ffmt::G,
-// prec=void, fflags::NONE). Two deferrals:
-//   - f32tos (ftos.ha:448) + its f32 Ryū sub-path (f32todecf32 +
-//     mulpow5inv/pow5_divpow2 + mulshift32 + the *32 helpers + the
-//     F32_POW5_*_BITCOUNT defs) → fold-5b (task #67), gated on the #143
-//     f32-arg-push cgen fix: f32tos must call math.f32bits(n), passing
-//     an f32 arg, which spills MOVSD (cstage) vs MOVSS (wwstage) →
-//     990-997 byte-id break. Not isolatable (f32bits IS the reinterpret),
-//     only fixable. f32tos IS a real Hare entry — it ships in #67.
+// SCOPE — the f64tos + f32tos shortest-representation subset (Hare's
+// ffmt::G, prec=void, fflags::NONE). f32tos (ftos.ha:448) + its f32 Ryū
+// sub-path (f32todecf32 + mulpow5inv/pow5_divpow2 + mulshift32 + the *32
+// helpers, reusing the shared u64-core + the f64 SPLIT2 tables — the f32
+// path has no separate tables, matching ftos_ryu.ha) ship here in fold-5b
+// (task #67): the gating #143 f32-arg-push cgen fix landed (aff7725, MOVSS
+// both stages), so f32tos's math.f32bits(n) call — passing an f32 arg — is
+// now byte-id-clean. One deferral remains:
 //   - the parametric fftosf/ffmt/fflags/ftosf surface → task #64 (needs
 //     io::handle/memio + a `(size|io::error)?` per appendrune (#158);
 //     for G/void/NONE the ffmt/fflags/precision/multiprecision-fallback
@@ -1681,6 +1680,195 @@ fn f64todecf64(mantissa: u64, exponent: u32) decf64 = {
 	return decf64 { exponent = (exp: i64), mantissa = output };
 };
 
+// ==== f32 Ryū sub-path (ftos_ryu.ha). The *32 helpers below mirror their
+// u64 siblings at 32-bit width; they reuse the SHARED f64computeinvpow5/
+// f64computepow5 (and thus the f64 SPLIT2 tables) per ftos_ryu.ha — there
+// is no separate f32 table. Same scalar-PARAM-mutation → copy-to-local,
+// comma-split, assert → os.assert, expr-yield → block divergences as the
+// f64 path above. ====
+
+// ref/hare/strconv/ftos_ryu.ha:52. Largest p with 5^p | value (32-bit).
+fn pow5fac32(v: u32) u32 = {
+	let value: u32 = v;
+	let count: u32 = 0u32;
+	for (true) {
+		os.assert(value != 0u32, "strconv.pow5fac32: value == 0");
+		let q: u32 = value / 5u32;
+		let r: u32 = value % 5u32;
+		if (r != 0u32) { break; };
+		value = q;
+		count += 1u32;
+	};
+	return count;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:67.
+fn pow5multiple32(v: u32, p: u32) bool = { return pow5fac32(v) >= p; };
+
+// ref/hare/strconv/ftos_ryu.ha:75.
+fn pow2multiple32(v: u32, p: u32) bool = {
+	os.assert(v > 0u32, "strconv.pow2multiple32: v == 0");
+	os.assert(p < 32u32, "strconv.pow2multiple32: p >= 32");
+	return (v & ((1u32 << p) - 1u32)) == 0u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:121. `m * a_lo` etc. carry an explicit
+// (m: u64) cast (Hare promotes the u32 operand; ww is strict). The bound
+// assert inlines U32_MAX's value: ww's types.U32_MAX is package-private
+// (lib/types/types.ww — no `export`), so Hare's `types::U32_MAX` can't be
+// referenced cross-package.
+fn mulshift32(m: u32, a: u64, s: u32) u32 = {
+	os.assert(s > 32u32, "strconv.mulshift32: s <= 32");
+	let a_lo: u64 = (a: u32): u64;
+	let a_hi: u64 = a >> 32u64;
+	let b0: u64 = (m: u64) * a_lo;
+	let b1: u64 = (m: u64) * a_hi;
+	let sum: u64 = (b0 >> 32u64) + b1;
+	let ss: u64 = sum >> ((s: u64) - 32u64);
+	os.assert(ss <= 4294967295u64, "strconv.mulshift32: ss > U32_MAX");
+	return ss: u32;
+};
+
+// ref/hare/strconv/ftos_ryu.ha:130.
+fn mulpow5inv_divpow2(m: u32, q: u32, j: i32) u32 = {
+	let pow5 = f64computeinvpow5(q);
+	return mulshift32(m, pow5.1 + 1u64, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:135.
+fn mulpow5_divpow2(m: u32, i: u32, j: i32) u32 = {
+	let pow5 = f64computepow5(i);
+	return mulshift32(m, pow5.1, (j: u32));
+};
+
+// ref/hare/strconv/ftos_ryu.ha:387. `exponent` rides i64 not Hare's i32,
+// for the same reason decf64 does: widening the field to a full second
+// eightbyte SIDESTEPS the #169 narrow-i32-field struct-return unpack (a
+// narrow i32 there unpacks MOVL wwstage vs MOVQ cstage). The value always
+// fits i32 (cast at the init_dec_mant_exp call site). `mantissa` stays u32
+// (Hare's width); the {u32, pad, i64} layout's first eightbyte holds
+// mantissa@0 + 4B pad and reads cleanly — byte-id CONFIRMED by the 990-997
+// gate (0-diff cs vs ww), not relied on as an ABI guarantee.
+type decf32 = struct { mantissa: u32, exponent: i64 };
+
+// ref/hare/strconv/ftos_ryu.ha:392. Shortest decimal of an f32:
+// value == mantissa * 10^exponent. `mantissa`/`exponent` are the raw
+// IEEE-754 fields of an f32.
+fn f32todecf32(mantissa: u32, exponent: u32) decf32 = {
+	let e2: i32 = (math.F32_EXPONENT_BIAS + math.F32_MANTISSA_BITS + 2u32): i32;
+	let m2: u32 = 0u32;
+	if (exponent == 0u32) {
+		e2 = 1i32 - e2;
+		m2 = mantissa;
+	} else {
+		e2 = (exponent: i32) - e2;
+		m2 = (1u32 << math.F32_MANTISSA_BITS) | mantissa;
+	};
+	let accept_bounds: bool = (m2 & 1u32) == 0u32;
+	let mv: u32 = 4u32 * m2;
+	let mp: u32 = mv + 2u32;
+	let mm_shift: u32 = ibool(mantissa != 0u32 || exponent <= 1u32): u32;
+	let mm: u32 = mv - 1u32 - mm_shift;
+	let vr: u32 = 0u32;
+	let vp: u32 = 0u32;
+	let vm: u32 = 0u32;
+	let e10: i32 = 0i32;
+	let vm_trailing_zeroes: bool = false;
+	let vr_trailing_zeroes: bool = false;
+	let last_removed_digit: u8 = 0u8;
+	if (e2 >= 0i32) {
+		let q: u32 = log10pow2(e2: u32);
+		e10 = q: i32;
+		let k: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q) - 1u32;
+		let i: i32 = -e2 + ((q + k): i32);
+		vr = mulpow5inv_divpow2(mv, q, i);
+		vp = mulpow5inv_divpow2(mp, q, i);
+		vm = mulpow5inv_divpow2(mm, q, i);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			let l: u32 = (F32_POW5_INV_BITCOUNT: u32) + pow5bits(q - 1u32) - 1u32;
+			// #168 dodge: div/mod on an inline N_CALL result emits a
+			// signed IDIVQ in wwstage; bind the call to a local first.
+			let lrd: u32 = mulpow5inv_divpow2(mv, q - 1u32,
+				-e2 + ((q + l): i32) - 1i32);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 9u32) {
+			if (mv % 5u32 == 0u32) {
+				vr_trailing_zeroes = pow5multiple32(mv, q);
+			} else if (accept_bounds) {
+				vm_trailing_zeroes = pow5multiple32(mm, q);
+			} else {
+				vp -= (ibool(pow5multiple32(mp, q)): u32);
+			};
+		};
+	} else {
+		let q: u32 = log10pow5((-e2): u32);
+		e10 = (q: i32) + e2;
+		let i: u32 = (-e2 - (q: i32)): u32;
+		let k: u32 = pow5bits(i) - (F32_POW5_BITCOUNT: u32);
+		let j: i32 = (q: i32) - (k: i32);
+		vr = mulpow5_divpow2(mv, i, j);
+		vp = mulpow5_divpow2(mp, i, j);
+		vm = mulpow5_divpow2(mm, i, j);
+		if (q != 0u32 && (vp - 1u32) / 10u32 <= vm / 10u32) {
+			j = (q: i32) - 1i32 - ((pow5bits(i + 1u32): i32) - (F32_POW5_BITCOUNT: i32));
+			// #168 dodge (see above): local-bind before the % 10.
+			let lrd: u32 = mulpow5_divpow2(mv, (i + 1u32), j);
+			last_removed_digit = (lrd % 10u32): u8;
+		};
+		if (q <= 1u32) {
+			vr_trailing_zeroes = true;
+			if (accept_bounds) {
+				vm_trailing_zeroes = mm_shift == 1u32;
+			} else {
+				vp -= 1u32;
+			};
+		} else if (q < 31u32) {
+			vr_trailing_zeroes = pow2multiple32(mv, q - 1u32);
+		};
+	};
+	let removed: i32 = 0i32;
+	let output: u32 = 0u32;
+	if (vm_trailing_zeroes || vr_trailing_zeroes) {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			vm_trailing_zeroes = vm_trailing_zeroes && ((vm - (vm / 10u32) * 10u32) == 0u32);
+			vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		if (vm_trailing_zeroes) {
+			for ((vm % 10u32) == 0u32) {
+				vr_trailing_zeroes = vr_trailing_zeroes && (last_removed_digit == 0u8);
+				last_removed_digit = (vr % 10u32): u8;
+				vr /= 10u32;
+				vp /= 10u32;
+				vm /= 10u32;
+				removed += 1i32;
+			};
+		};
+		if (vr_trailing_zeroes && last_removed_digit == 5u8 && vr % 2u32 == 0u32) {
+			last_removed_digit = 4u8;	// round to even
+		};
+		let cond1: bool = (vr == vm) && ((!accept_bounds) || (!vm_trailing_zeroes));
+		let cond2: bool = last_removed_digit >= 5u8;
+		output = vr + (ibool(cond1 || cond2): u32);
+	} else {
+		for ((vp / 10u32) > (vm / 10u32)) {
+			last_removed_digit = (vr % 10u32): u8;
+			vr /= 10u32;
+			vp /= 10u32;
+			vm /= 10u32;
+			removed += 1i32;
+		};
+		output = vr + (ibool(vr == vm || last_removed_digit >= 5u8): u32);
+	};
+	let exp: i32 = e10 + removed;
+	return decf32 { mantissa = output, exponent = (exp: i64) };
+};
+
 // ==== G-format encode layer (ftos.ha) — only the ffmt::G / prec=void /
 // fflags::NONE-REACHABLE logic. The SHOW_POINT/precision/E-vs-uppercase
 // arms (ftos.ha:88-105, 127-145, 170-213's zeros/caps) are UNREACHABLE
@@ -1889,6 +2077,67 @@ export fn f64tos(n: f64) str = {
 	return r;
 };
 
+// ref/hare/strconv/ftos.ha:448. f32 → shortest base-10 str. Same static-
+// buffer convention + G/void/NONE-inlined path as f64tos. f32bits(n)
+// passes an f32 arg → MOVSS both stages post-#143 (aff7725); this is the
+// piece fold-5b was gated on.
+//
+// Hare sizes this [14]u8 (ftos.ha:451: 1 + 1 + 1 + 7 + 1 + 1 + 2). Sized
+// 32 to reuse f64tos's proven byte-id-clean band: a no-rhs [N]u8 module
+// buffer at the size-16/24 band emits divergent DATAW counts cs≠ww (#43);
+// 32 emits 2 DATAW in both. The unused tail bytes are harmless.
+let f32tos_buf: [32]u8;
+
+export fn f32tos(n: f32) str = {
+	let bits: u32 = math.f32bits(n);
+	let mantissa: u32 = bits & math.F32_MANTISSA_MASK;
+	let exponent: u32 = (bits >> math.F32_MANTISSA_BITS) & math.F32_EXPONENT_MASK;
+	let sign: bool = (bits >> (math.F32_EXPONENT_BITS + math.F32_MANTISSA_BITS)) > 0u32;
+	let special: bool = exponent == math.F32_EXPONENT_MASK;
+
+	let o: i32 = 0i32;
+	let r: str;
+	r.ptr = &f32tos_buf[0];
+	// NaN carries no sign prefix (ftos.ha:331-333, before sign handling).
+	if (special && mantissa != 0u32) {
+		o = putstr(f32tos_buf[0:32], o, "nan");
+		r.len = o;
+		return r;
+	};
+	if (sign) {
+		f32tos_buf[o] = 45u8;	// '-'
+		o += 1i32;
+	};
+	if (special) {
+		o = putstr(f32tos_buf[0:32], o, "infinity");
+		r.len = o;
+		return r;
+	};
+	if (exponent == 0u32 && mantissa == 0u32) {
+		f32tos_buf[o] = 48u8;	// '0' (encode_zero, G/void/NONE)
+		o += 1i32;
+		r.len = o;
+		return r;
+	};
+
+	let d = decimal { ... };
+	// *decimal pointer for the field reads (the #170 dodge; see f64tos).
+	let pd: *decimal = &d;
+	let dd: decf32 = f32todecf32(mantissa, exponent);
+	init_dec_mant_exp(pd, (dd.mantissa: u64), (dd.exponent: i32));
+	trim(pd);
+	if (pd.nd == (0u64: size)) {
+		f32tos_buf[o] = 48u8;	// rounded to zero
+		o += 1i32;
+	} else if (pd.dp < -1i32 || (pd.dp - (pd.nd: i32)) > 2i32) {
+		o = encode_e_dec(pd, f32tos_buf[0:32], o);
+	} else {
+		o = encode_f_dec(pd, f32tos_buf[0:32], o);
+	};
+	r.len = o;
+	return r;
+};
+
 // strconv — Ryū float→string lookup tables + bit-count constants.
 // Mirrors ref/hare/strconv/ftos_ryu.ha:159-222 byte-exact. Pure data
 // fold (strconv #106 fold-5): no logic, consumed by ftos.ww's
@@ -1916,12 +2165,18 @@ package strconv;
 // power-of-five tables. Defined u8 (faithful); ftos.ww casts to u32/i32
 // at each use site (Hare promotes a u8 def inside mixed-width arithmetic;
 // ww is strict — explicit cast, project_int_machine_word_derived_limits).
-// The F32_POW5_*_BITCOUNT siblings (ftos_ryu.ha:162-163) land in fold-5b
-// (task #67) with their only consumer, f32todecf32 — omitted here to keep
-// this fold dead-code-free.
 def F64_POW5_INV_BITCOUNT: u8 = 125u8;
 def F64_POW5_BITCOUNT: u8 = 125u8;
 
+// ref/hare/strconv/ftos_ryu.ha:162-163. The f32 split-table bit-counts,
+// derived from the f64 siblings (Hare: F64_..._BITCOUNT - 64). Consumed by
+// f32todecf32 (ftos.ww), landed in fold-5b (task #67) — the f32 path reuses
+// the f64 SPLIT2 tables (via f64computeinvpow5/f64computepow5), so no
+// separate F32 tables exist (matches ftos_ryu.ha). u8 like the f64 defs;
+// ftos.ww casts to u32/i32 at each use.
+def F32_POW5_INV_BITCOUNT: u8 = F64_POW5_INV_BITCOUNT - 64u8;
+def F32_POW5_BITCOUNT: u8 = F64_POW5_BITCOUNT - 64u8;
+
 // ref/hare/strconv/ftos_ryu.ha:165-181.
 let F64_POW5_INV_SPLIT2: [15][2]u64 = [
 	[1u64, 2305843009213693952u64],