Philippe Mathieu-Daudé <f4...@amsat.org> writes: > Hi Alex, > > On 01/09/2018 09:22 AM, Alex Bennée wrote: >> This defines the same set of common constants for float 16 as defined >> for 32 and 64 bit floats. These are often used by target helper >> functions. I've also removed constants that are not used by anybody. >> >> Signed-off-by: Alex Bennée <alex.ben...@linaro.org> >> >> --- >> v2 >> - fixup constants, remove unused onces >> --- >> include/fpu/softfloat.h | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h >> index 8ab5d0df47..e64bf62f3d 100644 >> --- a/include/fpu/softfloat.h >> +++ b/include/fpu/softfloat.h >> @@ -368,6 +368,11 @@ static inline float16 float16_set_sign(float16 a, int >> sign) >> return make_float16((float16_val(a) & 0x7fff) | (sign << 15)); >> } >> >> +#define float16_zero make_float16(0) >> +#define float16_one make_float16(0x3a00) > > I still disagree with this one, it seems your bits 9/10 are inverted > (mantissa msb with biased exponent lsb). > > S EEEEE TTTTTTTTTT > 0x3a00 = 0 01110 1000000000 > > having: > S=0 > E=0b01110=14 > T=0b1000000000=512 > > I get: > (-1)^0 * 2^(14-15) * (1 + (2^-10) * 512) = 1 * 0.5 * (1 + 0.5) = 0.75 > > With 0x3c00 I get: > > S EEEEE TTTTTTTTTT > 0x3c00 = 0 01111 0000000000 > S=0 > E=0b01111=15 > T=0b0000000000=0 > > (-1)^0 * 2^(15-15) * (1 + (2^-10) * 0) = 1 * 2^0 * (1 + 0) = 1 > > The rest is OK. > > Changing by "#define float16_one make_float16(0x3c00)": > Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
Dam it, I thought I'd fixed them all. Thanks for the catch. > >> +#define float16_half make_float16(0x3800) >> +#define float16_infinity make_float16(0x7c00) >> + >> >> /*---------------------------------------------------------------------------- >> | The pattern for a default generated half-precision NaN. >> >> *----------------------------------------------------------------------------*/ >> @@ -474,8 +479,6 @@ static inline float32 float32_set_sign(float32 a, int >> sign) >> >> #define float32_zero make_float32(0) >> #define float32_one make_float32(0x3f800000) >> -#define float32_ln2 make_float32(0x3f317218) >> -#define float32_pi make_float32(0x40490fdb) >> #define float32_half make_float32(0x3f000000) >> #define float32_infinity make_float32(0x7f800000) >> >> @@ -588,7 +591,6 @@ static inline float64 float64_set_sign(float64 a, int >> sign) >> #define float64_zero make_float64(0) >> #define float64_one make_float64(0x3ff0000000000000LL) >> #define float64_ln2 make_float64(0x3fe62e42fefa39efLL) >> -#define float64_pi make_float64(0x400921fb54442d18LL) >> #define float64_half make_float64(0x3fe0000000000000LL) >> #define float64_infinity make_float64(0x7ff0000000000000LL) >> >> -- Alex Bennée
