RPCS3/rpcs3
1
0
Fork 0
mirror of https://github.com/RPCS3/rpcs3.git synced 2026-03-10 15:38:08 +01:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity

rsx: Improve comments/documentation around border color SEXT convert

Browse source
This commit is contained in:
kd-11 2026-02-21 14:03:04 +03:00 committed by kd-11
parent 3585881a6c
commit e22c83f4ce
1 changed files with 6 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
rpcs3/Emu/RSX/RSXTexture.cpp
View file

@ -315,6 +315,7 @@ namespace rsx
// Border color is broken on PS3. The SNORM behavior is completely broken and behaves like BIASED renormalization instead.
// To solve the mismatch, we need to first do a bit expansion on the value then store it as sign extended. The second part is a natural part of numbers on a binary system, so we only need to do the former.
// Note that the input color is in BE order (BGRA) so we reverse the mask to match.
static constexpr u32 expand4_lut[16] =
{
0x00000000u, // 0000
@ -335,7 +336,7 @@ namespace rsx
0xFFFFFFFFu // 1111
};
// Bit pattern expand and reverse BE -> LE using LUT
// Bit pattern expand
const u32 mask = expand4_lut[sext];
// Now we perform the compensation operation
@ -344,16 +345,14 @@ namespace rsx
// Load
const __m128i _0 = _mm_setzero_si128();
const __m128i _128 = _mm_set1_epi32(128);
const __m128i _127 = _mm_set1_epi32(127);
const __m128i _255 = _mm_set1_epi32(255);
const auto be_raw = be_t<u32>(raw);
__m128i v = _mm_cvtsi32_si128(static_cast<u32>(be_raw));
// Explode the bytes.
__m128i v = _mm_cvtsi32_si128(raw);
v = _mm_unpacklo_epi8(v, _0);
v = _mm_unpacklo_epi16(v, _0); // [ 0, 64, 255, 128 ]
v = _mm_unpacklo_epi16(v, _0);
// Conversion: x = (y - 128)
v = _mm_sub_epi32(v, _128); // [ -128, -64, 127, 0 ]
v = _mm_sub_epi32(v, _128);
// Convert to signed encoding (reverse sext)
v = _mm_slli_epi32(v, 24);