This is one of the simpler manipulations you could make to a floating
point number.
Signed-off-by: Alex Bennée
---
fpu/softfloat.c | 104 +++-
include/fpu/softfloat.h | 1 +
2 files changed, 32 insertions(+), 73 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 1a7f1cab10..b7ea56dfa5 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1662,6 +1662,37 @@ float64 uint16_to_float64(uint16_t a, float_status
*status)
return uint64_to_float64((uint64_t) a, status);
}
+/* Multiply A by 2 raised to the power N. */
+static decomposed_parts scalbn_decomposed(decomposed_parts a, int n,
+ float_status *s)
+{
+if (a.cls == float_class_normal) {
+a.exp += n;
+}
+return a;
+}
+
+float16 float16_scalbn(float16 a, int n, float_status *status)
+{
+decomposed_parts pa = float16_unpack_canonical(a, status);
+decomposed_parts pr = scalbn_decomposed(pa, n, status);
+return float16_round_pack_canonical(pr, status);
+}
+
+float32 float32_scalbn(float32 a, int n, float_status *status)
+{
+decomposed_parts pa = float32_unpack_canonical(a, status);
+decomposed_parts pr = scalbn_decomposed(pa, n, status);
+return float32_round_pack_canonical(pr, status);
+}
+
+float64 float64_scalbn(float64 a, int n, float_status *status)
+{
+decomposed_parts pa = float64_unpack_canonical(a, status);
+decomposed_parts pr = scalbn_decomposed(pa, n, status);
+return float64_round_pack_canonical(pr, status);
+}
+
/*
| Takes a 64-bit fixed-point value `absZ' with binary point between bits 6
| and 7, and returns the properly rounded 32-bit integer corresponding to the
@@ -6991,79 +7022,6 @@ MINMAX(32)
MINMAX(64)
-/* Multiply A by 2 raised to the power N. */
-float32 float32_scalbn(float32 a, int n, float_status *status)
-{
-flag aSign;
-int16_t aExp;
-uint32_t aSig;
-
-a = float32_squash_input_denormal(a, status);
-aSig = extractFloat32Frac( a );
-aExp = extractFloat32Exp( a );
-aSign = extractFloat32Sign( a );
-
-if ( aExp == 0xFF ) {
-if ( aSig ) {
-return propagateFloat32NaN(a, a, status);
-}
-return a;
-}
-if (aExp != 0) {
-aSig |= 0x0080;
-} else if (aSig == 0) {
-return a;
-} else {
-aExp++;
-}
-
-if (n > 0x200) {
-n = 0x200;
-} else if (n < -0x200) {
-n = -0x200;
-}
-
-aExp += n - 1;
-aSig <<= 7;
-return normalizeRoundAndPackFloat32(aSign, aExp, aSig, status);
-}
-
-float64 float64_scalbn(float64 a, int n, float_status *status)
-{
-flag aSign;
-int16_t aExp;
-uint64_t aSig;
-
-a = float64_squash_input_denormal(a, status);
-aSig = extractFloat64Frac( a );
-aExp = extractFloat64Exp( a );
-aSign = extractFloat64Sign( a );
-
-if ( aExp == 0x7FF ) {
-if ( aSig ) {
-return propagateFloat64NaN(a, a, status);
-}
-return a;
-}
-if (aExp != 0) {
-aSig |= LIT64( 0x0010 );
-} else if (aSig == 0) {
-return a;
-} else {
-aExp++;
-}
-
-if (n > 0x1000) {
-n = 0x1000;
-} else if (n < -0x1000) {
-n = -0x1000;
-}
-
-aExp += n - 1;
-aSig <<= 10;
-return normalizeRoundAndPackFloat64(aSign, aExp, aSig, status);
-}
-
floatx80 floatx80_scalbn(floatx80 a, int n, float_status *status)
{
flag aSign;
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 8ebde83251..c1224aab8c 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -353,6 +353,7 @@ float16 float16_sub(float16, float16, float_status *status);
float16 float16_mul(float16, float16, float_status *status);
float16 float16_muladd(float16, float16, float16, int, float_status *status);
float16 float16_div(float16, float16, float_status *status);
+float16 float16_scalbn(float16, int, float_status *status);
int float16_is_quiet_nan(float16, float_status *status);
int float16_is_signaling_nan(float16, float_status *status);
--
2.15.1
