motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-06 17:23:56 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

target-arm: A64: Add FRECPX (reciprocal exponent)

Browse source 
These are fairly simple exponent only estimation functions using helpers.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-id: 1394822294-14837-14-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Alex Bennée 2014-03-17 16:31:50 +00:00 • committed by Peter Maydell
parent a566da1b02
commit 8f0c6758b0
3 changed files with 130 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

59
target-arm/helper-a64.c
View file

@ -354,3 +354,62 @@ uint64_t HELPER(neon_addlp_u16)(uint64_t a)
tmp += (a >> 16) & 0x0000ffff0000ffffULL;
return tmp;
}
/* Floating-point reciprocal exponent - see FPRecpX in ARM ARM */
float32 HELPER(frecpx_f32)(float32 a, void *fpstp)
{
float_status *fpst = fpstp;
uint32_t val32, sbit;
int32_t exp;
if (float32_is_any_nan(a)) {
float32 nan = a;
if (float32_is_signaling_nan(a)) {
float_raise(float_flag_invalid, fpst);
nan = float32_maybe_silence_nan(a);
}
if (fpst->default_nan_mode) {
nan = float32_default_nan;
}
return nan;
}
val32 = float32_val(a);
sbit = 0x80000000ULL & val32;
exp = extract32(val32, 23, 8);
if (exp == 0) {
return make_float32(sbit | (0xfe << 23));
} else {
return make_float32(sbit | (~exp & 0xff) << 23);
}
}
float64 HELPER(frecpx_f64)(float64 a, void *fpstp)
{
float_status *fpst = fpstp;
uint64_t val64, sbit;
int64_t exp;
if (float64_is_any_nan(a)) {
float64 nan = a;
if (float64_is_signaling_nan(a)) {
float_raise(float_flag_invalid, fpst);
nan = float64_maybe_silence_nan(a);
}
if (fpst->default_nan_mode) {
nan = float64_default_nan;
}
return nan;
}
val64 = float64_val(a);
sbit = 0x8000000000000000ULL & val64;
exp = extract64(float64_val(a), 52, 11);
if (exp == 0) {
return make_float64(sbit | (0x7feULL << 52));
} else {
return make_float64(sbit | (~exp & 0x7ffULL) << 52);
}
}