diff options
Diffstat (limited to 'src/gallium/auxiliary/gallivm/lp_bld_swizzle.c')
| -rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_swizzle.c | 80 |
1 files changed, 58 insertions, 22 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_swizzle.c b/src/gallium/auxiliary/gallivm/lp_bld_swizzle.c index 08d817a28f5..79116bcf391 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_swizzle.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_swizzle.c @@ -217,6 +217,20 @@ lp_build_swizzle_scalar_aos(struct lp_build_context *bld, a = LLVMBuildBitCast(builder, a, lp_build_vec_type(bld->gallivm, type2), ""); + /* + * Vector element 0 is always channel X. + * + * 76 54 32 10 (array numbering) + * Little endian reg in: YX YX YX YX + * Little endian reg out: YY YY YY YY if shift right (shift == -1) + * XX XX XX XX if shift left (shift == 1) + * + * 01 23 45 67 (array numbering) + * Big endian reg in: XY XY XY XY + * Big endian reg out: YY YY YY YY if shift left (shift == 1) + * XX XX XX XX if shift right (shift == -1) + * + */ #ifdef PIPE_ARCH_LITTLE_ENDIAN shift = channel == 0 ? 1 : -1; #else @@ -240,10 +254,23 @@ lp_build_swizzle_scalar_aos(struct lp_build_context *bld, /* * Bit mask and recursive shifts * + * Little-endian registers: + * + * 7654 3210 + * WZYX WZYX .... WZYX <= input + * 00Y0 00Y0 .... 00Y0 <= mask + * 00YY 00YY .... 00YY <= shift right 1 (shift amount -1) + * YYYY YYYY .... YYYY <= shift left 2 (shift amount 2) + * + * Big-endian registers: + * + * 0123 4567 * XYZW XYZW .... XYZW <= input - * 0Y00 0Y00 .... 0Y00 - * YY00 YY00 .... YY00 - * YYYY YYYY .... YYYY <= output + * 0Y00 0Y00 .... 0Y00 <= mask + * YY00 YY00 .... YY00 <= shift left 1 (shift amount 1) + * YYYY YYYY .... YYYY <= shift right 2 (shift amount -2) + * + * shifts[] gives little-endian shift amounts; we need to negate for big-endian. */ struct lp_type type4; const int shifts[4][2] = { @@ -274,14 +301,15 @@ lp_build_swizzle_scalar_aos(struct lp_build_context *bld, LLVMValueRef tmp = NULL; int shift = shifts[channel][i]; -#ifdef PIPE_ARCH_LITTLE_ENDIAN + /* See endianness diagram above */ +#ifdef PIPE_ARCH_BIG_ENDIAN shift = -shift; #endif if(shift > 0) - tmp = LLVMBuildLShr(builder, a, lp_build_const_int_vec(bld->gallivm, type4, shift*type.width), ""); + tmp = LLVMBuildShl(builder, a, lp_build_const_int_vec(bld->gallivm, type4, shift*type.width), ""); if(shift < 0) - tmp = LLVMBuildShl(builder, a, lp_build_const_int_vec(bld->gallivm, type4, -shift*type.width), ""); + tmp = LLVMBuildLShr(builder, a, lp_build_const_int_vec(bld->gallivm, type4, -shift*type.width), ""); assert(tmp); if(tmp) @@ -474,21 +502,39 @@ lp_build_swizzle_aos(struct lp_build_context *bld, /* * Mask and shift the channels, trying to group as many channels in the - * same shift as possible + * same shift as possible. The shift amount is positive for shifts left + * and negative for shifts right. */ for (shift = -3; shift <= 3; ++shift) { uint64_t mask = 0; assert(type4.width <= sizeof(mask)*8); + /* + * Vector element numbers follow the XYZW order, so 0 is always X, etc. + * After widening 4 times we have: + * + * 3210 + * Little-endian register layout: WZYX + * + * 0123 + * Big-endian register layout: XYZW + * + * For little-endian, higher-numbered channels are obtained by a shift right + * (negative shift amount) and lower-numbered channels by a shift left + * (positive shift amount). The opposite is true for big-endian. + */ for (chan = 0; chan < 4; ++chan) { - /* FIXME: big endian */ - if (swizzles[chan] < 4 && - chan - swizzles[chan] == shift) { + if (swizzles[chan] < 4) { + /* We need to move channel swizzles[chan] into channel chan */ #ifdef PIPE_ARCH_LITTLE_ENDIAN - mask |= ((1ULL << type.width) - 1) << (swizzles[chan] * type.width); + if (swizzles[chan] - chan == -shift) { + mask |= ((1ULL << type.width) - 1) << (swizzles[chan] * type.width); + } #else - mask |= ((1ULL << type.width) - 1) << (type4.width - type.width) >> (swizzles[chan] * type.width); + if (swizzles[chan] - chan == shift) { + mask |= ((1ULL << type.width) - 1) << (type4.width - type.width) >> (swizzles[chan] * type.width); + } #endif } } @@ -502,21 +548,11 @@ lp_build_swizzle_aos(struct lp_build_context *bld, masked = LLVMBuildAnd(builder, a, lp_build_const_int_vec(bld->gallivm, type4, mask), ""); if (shift > 0) { -#ifdef PIPE_ARCH_LITTLE_ENDIAN shifted = LLVMBuildShl(builder, masked, lp_build_const_int_vec(bld->gallivm, type4, shift*type.width), ""); -#else - shifted = LLVMBuildLShr(builder, masked, - lp_build_const_int_vec(bld->gallivm, type4, shift*type.width), ""); -#endif } else if (shift < 0) { -#ifdef PIPE_ARCH_LITTLE_ENDIAN shifted = LLVMBuildLShr(builder, masked, lp_build_const_int_vec(bld->gallivm, type4, -shift*type.width), ""); -#else - shifted = LLVMBuildShl(builder, masked, - lp_build_const_int_vec(bld->gallivm, type4, -shift*type.width), ""); -#endif } else { shifted = masked; } |