Commit 0182fcd813 for qemu.org
commit 0182fcd813244def266e9ca4a274d565791b7fe1
Author: Max Chou <max.chou@sifive.com>
Date: Thu Feb 5 16:29:28 2026 +1000
fpu: Add saturate parameter to parts_uncanon
The OCP FP8 conversion operations have a parameter to control
saturate vs overflow. Add a parameter, currently always false.
Reviewed-by: Chao Liu <chao.liu.zevorn@gmail.com>
Signed-off-by: Max Chou <max.chou@sifive.com>
[rth: Split out of a larger patch]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index 4909ff7418..09be686645 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -258,9 +258,12 @@ static void partsN(canonicalize)(FloatPartsN *p, float_status *status,
* are FRAC_SHIFT bits that may require rounding at the bottom of the
* fraction; these bits will be removed. The exponent will be biased
* by EXP_BIAS and must be bounded by [EXP_MAX-1, 0].
+ *
+ * The saturate parameter controls saturation behavior for formats that
+ * support it -- when true, overflow produces max normal instead of infinity.
*/
static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
- const FloatFmt *fmt)
+ const FloatFmt *fmt, bool saturate)
{
const int exp_max = fmt->exp_max;
const int frac_shift = fmt->frac_shift;
@@ -269,7 +272,7 @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
const uint64_t frac_lsbm1 = round_mask ^ (round_mask >> 1);
const uint64_t roundeven_mask = round_mask | frac_lsb;
uint64_t inc;
- bool overflow_norm = false;
+ bool overflow_norm = saturate;
int exp, flags = 0;
switch (s->float_rounding_mode) {
@@ -294,11 +297,11 @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
break;
case float_round_up:
inc = p->sign ? 0 : round_mask;
- overflow_norm = p->sign;
+ overflow_norm |= p->sign;
break;
case float_round_down:
inc = p->sign ? round_mask : 0;
- overflow_norm = !p->sign;
+ overflow_norm |= !p->sign;
break;
case float_round_to_odd:
overflow_norm = true;
@@ -445,10 +448,10 @@ static void partsN(uncanon_normal)(FloatPartsN *p, float_status *s,
}
static void partsN(uncanon)(FloatPartsN *p, float_status *s,
- const FloatFmt *fmt)
+ const FloatFmt *fmt, bool saturate)
{
if (likely(is_anynorm(p->cls))) {
- parts_uncanon_normal(p, s, fmt);
+ parts_uncanon_normal(p, s, fmt, saturate);
} else {
switch (p->cls) {
case float_class_zero:
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 9d06a1bb59..b3c4104854 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -771,20 +771,20 @@ static void parts128_canonicalize(FloatParts128 *p, float_status *status,
PARTS_GENERIC_64_128(canonicalize, A)(A, S, F)
static void parts64_uncanon_normal(FloatParts64 *p, float_status *status,
- const FloatFmt *fmt);
+ const FloatFmt *fmt, bool saturate);
static void parts128_uncanon_normal(FloatParts128 *p, float_status *status,
- const FloatFmt *fmt);
+ const FloatFmt *fmt, bool saturate);
-#define parts_uncanon_normal(A, S, F) \
- PARTS_GENERIC_64_128(uncanon_normal, A)(A, S, F)
+#define parts_uncanon_normal(A, S, F, X) \
+ PARTS_GENERIC_64_128(uncanon_normal, A)(A, S, F, X)
static void parts64_uncanon(FloatParts64 *p, float_status *status,
- const FloatFmt *fmt);
+ const FloatFmt *fmt, bool saturate);
static void parts128_uncanon(FloatParts128 *p, float_status *status,
- const FloatFmt *fmt);
+ const FloatFmt *fmt, bool saturate);
-#define parts_uncanon(A, S, F) \
- PARTS_GENERIC_64_128(uncanon, A)(A, S, F)
+#define parts_uncanon(A, S, F, X) \
+ PARTS_GENERIC_64_128(uncanon, A)(A, S, F, X)
static void parts64_add_normal(FloatParts64 *a, FloatParts64 *b);
static void parts128_add_normal(FloatParts128 *a, FloatParts128 *b);
@@ -1699,7 +1699,7 @@ static float16 float16a_round_pack_canonical(FloatParts64 *p,
float_status *s,
const FloatFmt *params)
{
- parts_uncanon(p, s, params);
+ parts_uncanon(p, s, params, false);
return float16_pack_raw(p);
}
@@ -1712,7 +1712,7 @@ static float16 float16_round_pack_canonical(FloatParts64 *p,
static bfloat16 bfloat16_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- parts_uncanon(p, s, &bfloat16_params);
+ parts_uncanon(p, s, &bfloat16_params, false);
return bfloat16_pack_raw(p);
}
@@ -1726,7 +1726,7 @@ static void float32_unpack_canonical(FloatParts64 *p, float32 f,
static float32 float32_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- parts_uncanon(p, s, &float32_params);
+ parts_uncanon(p, s, &float32_params, false);
return float32_pack_raw(p);
}
@@ -1740,7 +1740,7 @@ static void float64_unpack_canonical(FloatParts64 *p, float64 f,
static float64 float64_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- parts_uncanon(p, s, &float64_params);
+ parts_uncanon(p, s, &float64_params, false);
return float64_pack_raw(p);
}
@@ -1789,7 +1789,7 @@ static float64 float64r32_pack_raw(FloatParts64 *p)
static float64 float64r32_round_pack_canonical(FloatParts64 *p,
float_status *s)
{
- parts_uncanon(p, s, &float32_params);
+ parts_uncanon(p, s, &float32_params, false);
return float64r32_pack_raw(p);
}
@@ -1803,7 +1803,7 @@ static void float128_unpack_canonical(FloatParts128 *p, float128 f,
static float128 float128_round_pack_canonical(FloatParts128 *p,
float_status *s)
{
- parts_uncanon(p, s, &float128_params);
+ parts_uncanon(p, s, &float128_params, false);
return float128_pack_raw(p);
}
@@ -1851,7 +1851,7 @@ static floatx80 floatx80_round_pack_canonical(FloatParts128 *p,
case float_class_normal:
case float_class_denormal:
if (s->floatx80_rounding_precision == floatx80_precision_x) {
- parts_uncanon_normal(p, s, fmt);
+ parts_uncanon_normal(p, s, fmt, false);
frac = p->frac_hi;
exp = p->exp;
} else {
@@ -1860,7 +1860,7 @@ static floatx80 floatx80_round_pack_canonical(FloatParts128 *p,
p64.sign = p->sign;
p64.exp = p->exp;
frac_truncjam(&p64, p);
- parts_uncanon_normal(&p64, s, fmt);
+ parts_uncanon_normal(&p64, s, fmt, false);
frac = p64.frac;
exp = p64.exp;
}
@@ -2258,7 +2258,7 @@ float16_muladd_scalbn(float16 a, float16 b, float16 c,
pr = parts_muladd_scalbn(&pa, &pb, &pc, scale, flags, status);
/* Round before applying negate result. */
- parts_uncanon(pr, status, &float16_params);
+ parts_uncanon(pr, status, &float16_params, false);
if ((flags & float_muladd_negate_result) && !is_nan(pr->cls)) {
pr->sign ^= 1;
}
@@ -2283,7 +2283,7 @@ float32_muladd_scalbn(float32 a, float32 b, float32 c,
pr = parts_muladd_scalbn(&pa, &pb, &pc, scale, flags, status);
/* Round before applying negate result. */
- parts_uncanon(pr, status, &float32_params);
+ parts_uncanon(pr, status, &float32_params, false);
if ((flags & float_muladd_negate_result) && !is_nan(pr->cls)) {
pr->sign ^= 1;
}
@@ -2302,7 +2302,7 @@ float64_muladd_scalbn(float64 a, float64 b, float64 c,
pr = parts_muladd_scalbn(&pa, &pb, &pc, scale, flags, status);
/* Round before applying negate result. */
- parts_uncanon(pr, status, &float64_params);
+ parts_uncanon(pr, status, &float64_params, false);
if ((flags & float_muladd_negate_result) && !is_nan(pr->cls)) {
pr->sign ^= 1;
}
@@ -2461,7 +2461,7 @@ float64 float64r32_muladd(float64 a, float64 b, float64 c,
pr = parts_muladd_scalbn(&pa, &pb, &pc, 0, flags, status);
/* Round before applying negate result. */
- parts_uncanon(pr, status, &float32_params);
+ parts_uncanon(pr, status, &float32_params, false);
if ((flags & float_muladd_negate_result) && !is_nan(pr->cls)) {
pr->sign ^= 1;
}
@@ -2479,7 +2479,7 @@ bfloat16 QEMU_FLATTEN bfloat16_muladd(bfloat16 a, bfloat16 b, bfloat16 c,
pr = parts_muladd_scalbn(&pa, &pb, &pc, 0, flags, status);
/* Round before applying negate result. */
- parts_uncanon(pr, status, &bfloat16_params);
+ parts_uncanon(pr, status, &bfloat16_params, false);
if ((flags & float_muladd_negate_result) && !is_nan(pr->cls)) {
pr->sign ^= 1;
}
@@ -2497,7 +2497,7 @@ float128 QEMU_FLATTEN float128_muladd(float128 a, float128 b, float128 c,
pr = parts_muladd_scalbn(&pa, &pb, &pc, 0, flags, status);
/* Round before applying negate result. */
- parts_uncanon(pr, status, &float128_params);
+ parts_uncanon(pr, status, &float128_params, false);
if ((flags & float_muladd_negate_result) && !is_nan(pr->cls)) {
pr->sign ^= 1;
}
@@ -5435,7 +5435,7 @@ static void parts_s390_divide_to_integer(FloatParts64 *a, FloatParts64 *b,
/* Round remainder to the target format */
*r = *r_precise;
status->float_exception_flags = 0;
- parts_uncanon(r, status, fmt);
+ parts_uncanon(r, status, fmt, false);
r_flags = status->float_exception_flags;
r->frac &= (1ULL << fmt->frac_size) - 1;
parts_canonicalize(r, status, fmt);