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target/hexagon: Use float32_muladd for helper_sffm[as]_lib

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There are multiple special cases for this instruction.
(1) The saturate to normal maximum instead of overflow to infinity is
    handled by the new float_round_nearest_even_max rounding mode.
(2) The 0 * n + c special case is handled by the new
    float_muladd_suppress_add_product_zero flag.
(3) The Inf - Inf -> 0 special case can be detected after the fact
    by examining float_flag_invalid_isi.

Reviewed-by: Brian Cain <brian.cain@oss.qualcomm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2024-12-08 14:33:22 -06:00
parent 904624ab8e
commit 316dca3985
1 changed files with 26 additions and 79 deletions
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105
target/hexagon/op_helper.c
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@ -1059,24 +1059,6 @@ float32 HELPER(sffma)(CPUHexagonState *env, float32 RxV,
return RxV;
}
static bool is_zero_prod(float32 a, float32 b)
{
return ((float32_is_zero(a) && is_finite(b)) ||
(float32_is_zero(b) && is_finite(a)));
}
static float32 check_nan(float32 dst, float32 x, float_status *fp_status)
{
float32 ret = dst;
if (float32_is_any_nan(x)) {
if (extract32(x, 22, 1) == 0) {
float_raise(float_flag_invalid, fp_status);
}
ret = make_float32(0xffffffff); /* nan */
}
return ret;
}
float32 HELPER(sffma_sc)(CPUHexagonState *env, float32 RxV,
float32 RsV, float32 RtV, float32 PuV)
{
@ -1098,78 +1080,43 @@ float32 HELPER(sffms)(CPUHexagonState *env, float32 RxV,
return RxV;
}
static bool is_inf_prod(int32_t a, int32_t b)
static float32 do_sffma_lib(CPUHexagonState *env, float32 RxV,
float32 RsV, float32 RtV, int negate)
{
return (float32_is_infinity(a) && float32_is_infinity(b)) ||
(float32_is_infinity(a) && is_finite(b) && !float32_is_zero(b)) ||
(float32_is_infinity(b) && is_finite(a) && !float32_is_zero(a));
int flags;
arch_fpop_start(env);
set_float_rounding_mode(float_round_nearest_even_max, &env->fp_status);
RxV = float32_muladd(RsV, RtV, RxV,
negate | float_muladd_suppress_add_product_zero,
&env->fp_status);
flags = get_float_exception_flags(&env->fp_status);
if (flags) {
/* Flags are suppressed by this instruction. */
set_float_exception_flags(0, &env->fp_status);
/* Return 0 for Inf - Inf. */
if (flags & float_flag_invalid_isi) {
RxV = 0;
}
}
arch_fpop_end(env);
return RxV;
}
float32 HELPER(sffma_lib)(CPUHexagonState *env, float32 RxV,
float32 RsV, float32 RtV)
{
bool infinp;
bool infminusinf;
float32 tmp;
arch_fpop_start(env);
set_float_rounding_mode(float_round_nearest_even, &env->fp_status);
infminusinf = float32_is_infinity(RxV) &&
is_inf_prod(RsV, RtV) &&
(fGETBIT(31, RsV ^ RxV ^ RtV) != 0);
infinp = float32_is_infinity(RxV) ||
float32_is_infinity(RtV) ||
float32_is_infinity(RsV);
RxV = check_nan(RxV, RxV, &env->fp_status);
RxV = check_nan(RxV, RsV, &env->fp_status);
RxV = check_nan(RxV, RtV, &env->fp_status);
tmp = internal_fmafx(RsV, RtV, RxV, 0, &env->fp_status);
if (!(float32_is_zero(RxV) && is_zero_prod(RsV, RtV))) {
RxV = tmp;
}
set_float_exception_flags(0, &env->fp_status);
if (float32_is_infinity(RxV) && !infinp) {
RxV = RxV - 1;
}
if (infminusinf) {
RxV = 0;
}
arch_fpop_end(env);
return RxV;
return do_sffma_lib(env, RxV, RsV, RtV, 0);
}
float32 HELPER(sffms_lib)(CPUHexagonState *env, float32 RxV,
float32 RsV, float32 RtV)
{
bool infinp;
bool infminusinf;
float32 tmp;
arch_fpop_start(env);
set_float_rounding_mode(float_round_nearest_even, &env->fp_status);
infminusinf = float32_is_infinity(RxV) &&
is_inf_prod(RsV, RtV) &&
(fGETBIT(31, RsV ^ RxV ^ RtV) == 0);
infinp = float32_is_infinity(RxV) ||
float32_is_infinity(RtV) ||
float32_is_infinity(RsV);
RxV = check_nan(RxV, RxV, &env->fp_status);
RxV = check_nan(RxV, RsV, &env->fp_status);
RxV = check_nan(RxV, RtV, &env->fp_status);
float32 minus_RsV = float32_sub(float32_zero, RsV, &env->fp_status);
tmp = internal_fmafx(minus_RsV, RtV, RxV, 0, &env->fp_status);
if (!(float32_is_zero(RxV) && is_zero_prod(RsV, RtV))) {
RxV = tmp;
}
set_float_exception_flags(0, &env->fp_status);
if (float32_is_infinity(RxV) && !infinp) {
RxV = RxV - 1;
}
if (infminusinf) {
RxV = 0;
}
arch_fpop_end(env);
return RxV;
return do_sffma_lib(env, RxV, RsV, RtV, float_muladd_negate_product);
}
float64 HELPER(dfmpyfix)(CPUHexagonState *env, float64 RssV, float64 RttV)