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| author | Ozkan Sezer <sezeroz@gmail.com> | 2017-08-17 21:30:29 -0400 |
|---|---|---|
| committer | Ozkan Sezer <sezeroz@gmail.com> | 2017-08-17 21:30:29 -0400 |
| commit | 536e1ee7526a6d832d74ad6338f014ce30f4d8ba (patch) | |
| tree | 7e692d65ce4bdc6adc140c3cf42894c0d91abf4e /include/SDL_bits.h | |
| parent | 2225929c31bb523a6619623313fbda2365d27644 (diff) | |
| download | sdl-536e1ee7526a6d832d74ad6338f014ce30f4d8ba.tar.gz | |
SDL_bits.h: add __builtin_clz equivalent for Watcom/x86 as inline asm
Partially fixes Bugzilla #3758.
Diffstat (limited to 'include/SDL_bits.h')
| -rw-r--r-- | include/SDL_bits.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/SDL_bits.h b/include/SDL_bits.h index f12f2c9a1..60cedc414 100644 --- a/include/SDL_bits.h +++ b/include/SDL_bits.h @@ -47,6 +47,16 @@ extern "C" { * * \return Index of the most significant bit, or -1 if the value is 0. */ +#if defined(__WATCOMC__) && defined(__386__) +extern _inline int _SDL_clz_watcom (Uint32); +#pragma aux _SDL_clz_watcom = \ + "bsr eax, eax" \ + "xor eax, 31" \ + parm [eax] nomemory \ + value [eax] \ + modify exact [eax] nomemory; +#endif + SDL_FORCE_INLINE int SDL_MostSignificantBitIndex32(Uint32 x) { @@ -58,6 +68,11 @@ SDL_MostSignificantBitIndex32(Uint32 x) return -1; } return 31 - __builtin_clz(x); +#elif defined(__WATCOMC__) && defined(__386__) + if (x == 0) { + return -1; + } + return 31 - _SDL_clz_watcom(x); #else /* Based off of Bit Twiddling Hacks by Sean Eron Anderson * <seander@cs.stanford.edu>, released in the public domain. |