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target-alpha: Make use of fp_status.flush_inputs_to_zero.

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This softfp feature post-dates the last major update to the Alpha
fpu translation.  We can make use of this to eliminate at least
one helper function that was performing this operation by hand.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
This commit is contained in:
Richard Henderson 2012-03-24 09:51:14 -07:00 committed by Blue Swirl
parent c30827555d
commit 743434099d
5 changed files with 26 additions and 50 deletions
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1
target-alpha/cpu.h
View file

@ -234,7 +234,6 @@ struct CPUAlphaState {
uint8_t fpcr_exc_mask;
uint8_t fpcr_dyn_round;
uint8_t fpcr_flush_to_zero;
uint8_t fpcr_dnz;
uint8_t fpcr_dnod;
uint8_t fpcr_undz;

44
target-alpha/fpu_helper.c
View file

@ -88,21 +88,17 @@ void helper_fp_exc_raise_s(CPUAlphaState *env, uint32_t exc, uint32_t regno)
}
}
/* Input remapping without software completion. Handle denormal-map-to-zero
and trap for all other non-finite numbers. */
uint64_t helper_ieee_input(CPUAlphaState *env, uint64_t val)
/* Input handing without software completion. Trap for all
non-finite numbers. */
void helper_ieee_input(CPUAlphaState *env, uint64_t val)
{
uint32_t exp = (uint32_t)(val >> 52) & 0x7ff;
uint64_t frac = val & 0xfffffffffffffull;
if (exp == 0) {
if (frac != 0) {
/* If DNZ is set flush denormals to zero on input. */
if (env->fpcr_dnz) {
val &= 1ull << 63;
} else {
arith_excp(env, GETPC(), EXC_M_UNF, 0);
}
/* Denormals without DNZ set raise an exception. */
if (frac != 0 && !env->fp_status.flush_inputs_to_zero) {
arith_excp(env, GETPC(), EXC_M_UNF, 0);
}
} else if (exp == 0x7ff) {
/* Infinity or NaN. */
@ -111,43 +107,23 @@ uint64_t helper_ieee_input(CPUAlphaState *env, uint64_t val)
just emulates the insn to figure out what exception to use. */
arith_excp(env, GETPC(), frac ? EXC_M_INV : EXC_M_FOV, 0);
}
return val;
}
/* Similar, but does not trap for infinities. Used for comparisons. */
uint64_t helper_ieee_input_cmp(CPUAlphaState *env, uint64_t val)
void helper_ieee_input_cmp(CPUAlphaState *env, uint64_t val)
{
uint32_t exp = (uint32_t)(val >> 52) & 0x7ff;
uint64_t frac = val & 0xfffffffffffffull;
if (exp == 0) {
if (frac != 0) {
/* If DNZ is set flush denormals to zero on input. */
if (env->fpcr_dnz) {
val &= 1ull << 63;
} else {
arith_excp(env, GETPC(), EXC_M_UNF, 0);
}
/* Denormals without DNZ set raise an exception. */
if (frac != 0 && !env->fp_status.flush_inputs_to_zero) {
arith_excp(env, GETPC(), EXC_M_UNF, 0);
}
} else if (exp == 0x7ff && frac) {
/* NaN. */
arith_excp(env, GETPC(), EXC_M_INV, 0);
}
return val;
}
/* Input remapping with software completion enabled. All we have to do
is handle denormal-map-to-zero; all other inputs get exceptions as
needed from the actual operation. */
uint64_t helper_ieee_input_s(CPUAlphaState *env, uint64_t val)
{
if (env->fpcr_dnz) {
uint32_t exp = (uint32_t)(val >> 52) & 0x7ff;
if (exp == 0) {
val &= 1ull << 63;
}
}
return val;
}
/* F floating (VAX) */

8
target-alpha/helper.c
View file

@ -82,7 +82,7 @@ uint64_t cpu_alpha_load_fpcr (CPUAlphaState *env)
break;
}
if (env->fpcr_dnz) {
if (env->fp_status.flush_inputs_to_zero) {
r |= FPCR_DNZ;
}
if (env->fpcr_dnod) {
@ -151,12 +151,10 @@ void cpu_alpha_store_fpcr (CPUAlphaState *env, uint64_t val)
}
env->fpcr_dyn_round = t;
env->fpcr_flush_to_zero
= (val & (FPCR_UNDZ|FPCR_UNFD)) == (FPCR_UNDZ|FPCR_UNFD);
env->fpcr_dnz = (val & FPCR_DNZ) != 0;
env->fpcr_dnod = (val & FPCR_DNOD) != 0;
env->fpcr_undz = (val & FPCR_UNDZ) != 0;
env->fpcr_flush_to_zero = env->fpcr_dnod & env->fpcr_undz;
env->fp_status.flush_inputs_to_zero = (val & FPCR_DNZ) != 0;
}
uint64_t helper_load_fpcr(CPUAlphaState *env)

5
target-alpha/helper.h
View file

@ -95,9 +95,8 @@ DEF_HELPER_FLAGS_1(fp_exc_get, TCG_CALL_CONST | TCG_CALL_PURE, i32, env)
DEF_HELPER_3(fp_exc_raise, void, env, i32, i32)
DEF_HELPER_3(fp_exc_raise_s, void, env, i32, i32)
DEF_HELPER_2(ieee_input, i64, env, i64)
DEF_HELPER_2(ieee_input_cmp, i64, env, i64)
DEF_HELPER_2(ieee_input_s, i64, env, i64)
DEF_HELPER_2(ieee_input, void, env, i64)
DEF_HELPER_2(ieee_input_cmp, void, env, i64)
#if !defined (CONFIG_USER_ONLY)
DEF_HELPER_2(hw_ret, void, env, i64)

18
target-alpha/translate.c
View file

@ -661,15 +661,19 @@ static void gen_qual_flushzero(DisasContext *ctx, int fn11)
static TCGv gen_ieee_input(int reg, int fn11, int is_cmp)
{
TCGv val = tcg_temp_new();
TCGv val;
if (reg == 31) {
tcg_gen_movi_i64(val, 0);
} else if (fn11 & QUAL_S) {
gen_helper_ieee_input_s(val, cpu_env, cpu_fir[reg]);
} else if (is_cmp) {
gen_helper_ieee_input_cmp(val, cpu_env, cpu_fir[reg]);
val = tcg_const_i64(0);
} else {
gen_helper_ieee_input(val, cpu_env, cpu_fir[reg]);
if ((fn11 & QUAL_S) == 0) {
if (is_cmp) {
gen_helper_ieee_input_cmp(cpu_env, cpu_fir[reg]);
} else {
gen_helper_ieee_input(cpu_env, cpu_fir[reg]);
}
}
val = tcg_temp_new();
tcg_gen_mov_i64(val, cpu_fir[reg]);
}
return val;
}