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target/ppc: reduce usage of fpscr_set_rounding_mode

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It is preferable to store the current rounding mode and retore from that
than recalculating from fpscr, so we changed the behavior of do_fri and
VSX_ROUND to do it like that.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bruno Larsen (billionai) <bruno.larsen@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210521201759.85475-4-bruno.larsen@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Bruno Larsen (billionai) 2021-05-21 17:17:53 -03:00 committed by David Gibson
parent a3f5c31539
commit 63d06e90e6
1 changed files with 5 additions and 3 deletions
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8
target/ppc/fpu_helper.c
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@ -822,6 +822,7 @@ static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
int rounding_mode) int rounding_mode)
{ {
CPU_DoubleU farg; CPU_DoubleU farg;
FloatRoundMode old_rounding_mode = get_float_rounding_mode(&env->fp_status);
farg.ll = arg; farg.ll = arg;
@ -834,8 +835,7 @@ static inline uint64_t do_fri(CPUPPCState *env, uint64_t arg,
float_flag_inexact; float_flag_inexact;
set_float_rounding_mode(rounding_mode, &env->fp_status); set_float_rounding_mode(rounding_mode, &env->fp_status);
farg.ll = float64_round_to_int(farg.d, &env->fp_status); farg.ll = float64_round_to_int(farg.d, &env->fp_status);
/* Restore rounding mode from FPSCR */ set_float_rounding_mode(old_rounding_mode, &env->fp_status);
fpscr_set_rounding_mode(env);
/* fri* does not set FPSCR[XX] */ /* fri* does not set FPSCR[XX] */
if (!inexact) { if (!inexact) {
@ -3136,8 +3136,10 @@ void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb) \
{ \ { \
ppc_vsr_t t = *xt; \ ppc_vsr_t t = *xt; \
int i; \ int i; \
FloatRoundMode curr_rounding_mode; \
\ \
if (rmode != FLOAT_ROUND_CURRENT) { \ if (rmode != FLOAT_ROUND_CURRENT) { \
curr_rounding_mode = get_float_rounding_mode(&env->fp_status); \
set_float_rounding_mode(rmode, &env->fp_status); \ set_float_rounding_mode(rmode, &env->fp_status); \
} \ } \
\ \
@ -3160,7 +3162,7 @@ void helper_##op(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb) \
* mode from FPSCR \ * mode from FPSCR \
*/ \ */ \
if (rmode != FLOAT_ROUND_CURRENT) { \ if (rmode != FLOAT_ROUND_CURRENT) { \
fpscr_set_rounding_mode(env); \ set_float_rounding_mode(curr_rounding_mode, &env->fp_status); \
env->fp_status.float_exception_flags &= ~float_flag_inexact; \ env->fp_status.float_exception_flags &= ~float_flag_inexact; \
} \ } \
\ \