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target/ppc: Add helper for fsqrts

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Use float64r32_sqrt.  Fixes a double-rounding issue with performing
the compuation in float64 and then rounding afterward.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-30-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
This commit is contained in:
Richard Henderson 2021-12-17 17:57:16 +01:00 committed by Cédric Le Goater
parent d04ca895dc
commit 41ae890d08
3 changed files with 14 additions and 2 deletions
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12
target/ppc/fpu_helper.c
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@ -775,6 +775,18 @@ float64 helper_fsqrt(CPUPPCState *env, float64 arg)
return ret;
}
/* fsqrts - fsqrts. */
float64 helper_fsqrts(CPUPPCState *env, float64 arg)
{
float64 ret = float64r32_sqrt(arg, &env->fp_status);
int flags = get_float_exception_flags(&env->fp_status);
if (unlikely(flags & float_flag_invalid)) {
float_invalid_op_sqrt(env, flags, 1, GETPC());
}
return ret;
}
/* fre - fre. */
float64 helper_fre(CPUPPCState *env, float64 arg)
{

1
target/ppc/helper.h
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@ -106,6 +106,7 @@ DEF_HELPER_4(fmsubs, i64, env, i64, i64, i64)
DEF_HELPER_4(fnmadds, i64, env, i64, i64, i64)
DEF_HELPER_4(fnmsubs, i64, env, i64, i64, i64)
DEF_HELPER_2(fsqrt, f64, env, f64)
DEF_HELPER_2(fsqrts, f64, env, f64)
DEF_HELPER_2(fre, i64, env, i64)
DEF_HELPER_2(fres, i64, env, i64)
DEF_HELPER_2(frsqrte, i64, env, i64)

3
target/ppc/translate/fp-impl.c.inc
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@ -270,8 +270,7 @@ static void gen_fsqrts(DisasContext *ctx)
t1 = tcg_temp_new_i64();
gen_reset_fpstatus();
get_fpr(t0, rB(ctx->opcode));
gen_helper_fsqrt(t1, cpu_env, t0);
gen_helper_frsp(t1, cpu_env, t1);
gen_helper_fsqrts(t1, cpu_env, t0);
set_fpr(rD(ctx->opcode), t1);
gen_compute_fprf_float64(t1);
if (unlikely(Rc(ctx->opcode) != 0)) {