On 12/03/2018 09:09, Dennis Clarke wrote: > /* 128-bit floating point has at most 38 digits > * of reasonable precision. We should be able to > * load in a constant value for pi using : > * > * 3.1415926535 8979323846 2643383279 > * 5028841971 6939937510 > * > * The result should be a 16-byte big endian machines > * representation in memory thus : > * > * 40 00 92 1f b5 44 42 d1 8469 89 8c c5 17 01 b8 > * > * We can try to load in some constants and hope we get > * a fully reasonable in memory value. > */ Oh, I didn't know about __float128. https://gcc.gnu.org/onlinedocs/gcc/Floating-Types.html $ cat float.c #include <stdio.h> #include <string.h> static __float128 pi = 3.1415926535897932384626433832795028841971693993751q; #define N (sizeof pi) int main(void) { int i; unsigned char buf[N]; memcpy(buf, &pi, N); for (i = 0; i < N; ++i) printf("%02x ", buf[i]); printf("\n"); return 0; } $ gcc-7 -Wall -O2 float.c && ./a.out b8 01 17 c5 8c 89 69 84 d1 42 44 b5 1f 92 00 40 (This is an amd64 little-endian system.)
