diff options
| -rw-r--r-- | src/mesa/main/imports.h | 21 | ||||
| -rw-r--r-- | src/mesa/main/teximage.c | 23 |
2 files changed, 24 insertions, 20 deletions
diff --git a/src/mesa/main/imports.h b/src/mesa/main/imports.h index ce7baabe2c7..3fa1db02aee 100644 --- a/src/mesa/main/imports.h +++ b/src/mesa/main/imports.h @@ -486,6 +486,27 @@ _mesa_next_pow_two_64(uint64_t x) } +/* + * Returns the floor form of binary logarithm for a 32-bit integer. + */ +static INLINE GLuint +_mesa_logbase2(GLuint n) +{ +#if defined(__GNUC__) && \ + ((__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || __GNUC__ >= 4) + return (31 - __builtin_clz(n | 1)); +#else + GLuint pos = 0; + if (n >= 1<<16) { n >>= 16; pos += 16; } + if (n >= 1<< 8) { n >>= 8; pos += 8; } + if (n >= 1<< 4) { n >>= 4; pos += 4; } + if (n >= 1<< 2) { n >>= 2; pos += 2; } + if (n >= 1<< 1) { pos += 1; } + return pos; +#endif +} + + /** * Return 1 if this is a little endian machine, 0 if big endian. */ diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c index 3e429110ae9..0827cb883e8 100644 --- a/src/mesa/main/teximage.c +++ b/src/mesa/main/teximage.c @@ -80,23 +80,6 @@ _mesa_free_texmemory(void *m) } -/* - * Returns the floor form of binary logarithm for a 32-bit integer. - */ -static GLuint -logbase2(GLuint n) -{ - GLuint pos = 0; - if (n >= 1<<16) { n >>= 16; pos += 16; } - if (n >= 1<< 8) { n >>= 8; pos += 8; } - if (n >= 1<< 4) { n >>= 4; pos += 4; } - if (n >= 1<< 2) { n >>= 2; pos += 2; } - if (n >= 1<< 1) { pos += 1; } - return pos; -} - - - /** * Return the simple base format for a given internal texture format. * For example, given GL_LUMINANCE12_ALPHA4, return GL_LUMINANCE_ALPHA. @@ -1155,7 +1138,7 @@ _mesa_init_teximage_fields(struct gl_context *ctx, GLenum target, img->Depth = depth; img->Width2 = width - 2 * border; /* == 1 << img->WidthLog2; */ - img->WidthLog2 = logbase2(img->Width2); + img->WidthLog2 = _mesa_logbase2(img->Width2); if (height == 1) { /* 1-D texture */ img->Height2 = 1; @@ -1163,7 +1146,7 @@ _mesa_init_teximage_fields(struct gl_context *ctx, GLenum target, } else { img->Height2 = height - 2 * border; /* == 1 << img->HeightLog2; */ - img->HeightLog2 = logbase2(img->Height2); + img->HeightLog2 = _mesa_logbase2(img->Height2); } if (depth == 1) { /* 2-D texture */ @@ -1172,7 +1155,7 @@ _mesa_init_teximage_fields(struct gl_context *ctx, GLenum target, } else { img->Depth2 = depth - 2 * border; /* == 1 << img->DepthLog2; */ - img->DepthLog2 = logbase2(img->Depth2); + img->DepthLog2 = _mesa_logbase2(img->Depth2); } img->MaxLog2 = MAX2(img->WidthLog2, img->HeightLog2); |