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authorRichard Henderson <richard.henderson@linaro.org>2020-11-09 19:08:30 -0800
committerRichard Henderson <richard.henderson@linaro.org>2021-05-16 07:13:51 -0500
commit463e45dcb4aa1a878b5ae5c6bbaf4ae70e24bf50 (patch)
tree11b2dfc3e24b7ac6dbc3060443e6f56dbfe9027d /fpu/softfloat.c
parent5ffb6bd9c44763a0ee11981c632b9be96ec68d8c (diff)
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softfloat: Introduce sh[lr]_double primitives
Have x86_64 assembly for them, with a fallback. This avoids shuffling values through %cl in the x86 case. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'fpu/softfloat.c')
-rw-r--r--fpu/softfloat.c102
1 files changed, 79 insertions, 23 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 571309e..3468995 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -957,15 +957,12 @@ static int frac128_normalize(FloatParts128 *a)
{
if (a->frac_hi) {
int shl = clz64(a->frac_hi);
- if (shl) {
- int shr = 64 - shl;
- a->frac_hi = (a->frac_hi << shl) | (a->frac_lo >> shr);
- a->frac_lo = (a->frac_lo << shl);
- }
+ a->frac_hi = shl_double(a->frac_hi, a->frac_lo, shl);
+ a->frac_lo <<= shl;
return shl;
} else if (a->frac_lo) {
int shl = clz64(a->frac_lo);
- a->frac_hi = (a->frac_lo << shl);
+ a->frac_hi = a->frac_lo << shl;
a->frac_lo = 0;
return shl + 64;
}
@@ -976,7 +973,7 @@ static int frac256_normalize(FloatParts256 *a)
{
uint64_t a0 = a->frac_hi, a1 = a->frac_hm;
uint64_t a2 = a->frac_lm, a3 = a->frac_lo;
- int ret, shl, shr;
+ int ret, shl;
if (likely(a0)) {
shl = clz64(a0);
@@ -1006,11 +1003,10 @@ static int frac256_normalize(FloatParts256 *a)
ret += shl;
}
- shr = -shl & 63;
- a0 = (a0 << shl) | (a1 >> shr);
- a1 = (a1 << shl) | (a2 >> shr);
- a2 = (a2 << shl) | (a3 >> shr);
- a3 = (a3 << shl);
+ a0 = shl_double(a0, a1, shl);
+ a1 = shl_double(a1, a2, shl);
+ a2 = shl_double(a2, a3, shl);
+ a3 <<= shl;
done:
a->frac_hi = a0;
@@ -1029,7 +1025,20 @@ static void frac64_shl(FloatParts64 *a, int c)
static void frac128_shl(FloatParts128 *a, int c)
{
- shift128Left(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo);
+ uint64_t a0 = a->frac_hi, a1 = a->frac_lo;
+
+ if (c & 64) {
+ a0 = a1, a1 = 0;
+ }
+
+ c &= 63;
+ if (c) {
+ a0 = shl_double(a0, a1, c);
+ a1 = a1 << c;
+ }
+
+ a->frac_hi = a0;
+ a->frac_lo = a1;
}
#define frac_shl(A, C) FRAC_GENERIC_64_128(shl, A)(A, C)
@@ -1041,19 +1050,68 @@ static void frac64_shr(FloatParts64 *a, int c)
static void frac128_shr(FloatParts128 *a, int c)
{
- shift128Right(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo);
+ uint64_t a0 = a->frac_hi, a1 = a->frac_lo;
+
+ if (c & 64) {
+ a1 = a0, a0 = 0;
+ }
+
+ c &= 63;
+ if (c) {
+ a1 = shr_double(a0, a1, c);
+ a0 = a0 >> c;
+ }
+
+ a->frac_hi = a0;
+ a->frac_lo = a1;
}
#define frac_shr(A, C) FRAC_GENERIC_64_128(shr, A)(A, C)
static void frac64_shrjam(FloatParts64 *a, int c)
{
- shift64RightJamming(a->frac, c, &a->frac);
+ uint64_t a0 = a->frac;
+
+ if (likely(c != 0)) {
+ if (likely(c < 64)) {
+ a0 = (a0 >> c) | (shr_double(a0, 0, c) != 0);
+ } else {
+ a0 = a0 != 0;
+ }
+ a->frac = a0;
+ }
}
static void frac128_shrjam(FloatParts128 *a, int c)
{
- shift128RightJamming(a->frac_hi, a->frac_lo, c, &a->frac_hi, &a->frac_lo);
+ uint64_t a0 = a->frac_hi, a1 = a->frac_lo;
+ uint64_t sticky = 0;
+
+ if (unlikely(c == 0)) {
+ return;
+ } else if (likely(c < 64)) {
+ /* nothing */
+ } else if (likely(c < 128)) {
+ sticky = a1;
+ a1 = a0;
+ a0 = 0;
+ c &= 63;
+ if (c == 0) {
+ goto done;
+ }
+ } else {
+ sticky = a0 | a1;
+ a0 = a1 = 0;
+ goto done;
+ }
+
+ sticky |= shr_double(a1, 0, c);
+ a1 = shr_double(a0, a1, c);
+ a0 = a0 >> c;
+
+ done:
+ a->frac_lo = a1 | (sticky != 0);
+ a->frac_hi = a0;
}
static void frac256_shrjam(FloatParts256 *a, int c)
@@ -1061,7 +1119,6 @@ static void frac256_shrjam(FloatParts256 *a, int c)
uint64_t a0 = a->frac_hi, a1 = a->frac_hm;
uint64_t a2 = a->frac_lm, a3 = a->frac_lo;
uint64_t sticky = 0;
- int invc;
if (unlikely(c == 0)) {
return;
@@ -1086,12 +1143,11 @@ static void frac256_shrjam(FloatParts256 *a, int c)
goto done;
}
- invc = -c & 63;
- sticky |= a3 << invc;
- a3 = (a3 >> c) | (a2 << invc);
- a2 = (a2 >> c) | (a1 << invc);
- a1 = (a1 >> c) | (a0 << invc);
- a0 = (a0 >> c);
+ sticky |= shr_double(a3, 0, c);
+ a3 = shr_double(a2, a3, c);
+ a2 = shr_double(a1, a2, c);
+ a1 = shr_double(a0, a1, c);
+ a0 = a0 >> c;
done:
a->frac_lo = a3 | (sticky != 0);