diff options
Diffstat (limited to 'src/gallium/auxiliary/tgsi/tgsi_sse2.c')
| -rw-r--r-- | src/gallium/auxiliary/tgsi/tgsi_sse2.c | 35 |
1 files changed, 32 insertions, 3 deletions
diff --git a/src/gallium/auxiliary/tgsi/tgsi_sse2.c b/src/gallium/auxiliary/tgsi/tgsi_sse2.c index c115956c5d..4d59106dbf 100644 --- a/src/gallium/auxiliary/tgsi/tgsi_sse2.c +++ b/src/gallium/auxiliary/tgsi/tgsi_sse2.c @@ -69,6 +69,9 @@ #define TEMP_R0 TGSI_EXEC_TEMP_R0 #define TEMP_ADDR TGSI_EXEC_TEMP_ADDR +#define TEMP_EXEC_MASK_I TGSI_EXEC_MASK_I +#define TEMP_EXEC_MASK_C TGSI_EXEC_MASK_C + /** * X86 utility functions. @@ -230,6 +233,9 @@ emit_const( int indirectIndex ) { if (indirect) { + /* 'vec' is the offset from the address register's value. + * We're loading CONST[ADDR+vec] into an xmm register. + */ struct x86_reg r0 = get_input_base(); struct x86_reg r1 = get_output_base(); uint i; @@ -240,18 +246,40 @@ emit_const( x86_push( func, r0 ); x86_push( func, r1 ); + /* + * Loop over the four pixels or vertices in the quad. + * Get the value of the address (offset) register for pixel/vertex[i], + * add it to the src offset and index into the constant buffer. + * Note that we're working on SOA data. + * If any of the pixel/vertex execution channels are unused their + * values will be garbage. It's very important that we don't use + * those garbage values as indexes into the constant buffer since + * that'll cause segfaults. + * The solution is to bitwise-AND the offset with the execution mask + * register whose values are either 0 or ~0. + * The caller must setup the execution mask register to indicate + * which channels are valid/alive before running the shader. + * The execution mask will also figure into loops and conditionals + * someday. + */ for (i = 0; i < QUAD_SIZE; i++) { - x86_lea( func, r0, get_const( vec, chan ) ); + /* r1 = address register[i] */ x86_mov( func, r1, x86_make_disp( get_temp( TEMP_ADDR, CHAN_X ), i * 4 ) ); + /* r0 = execution mask[i] */ + x86_mov( func, r0, x86_make_disp( get_temp( TEMP_EXEC_MASK_I, TEMP_EXEC_MASK_C ), i * 4 ) ); + /* r1 = r1 & r0 */ + x86_and( func, r1, r0 ); + /* r0 = 'vec', the offset */ + x86_lea( func, r0, get_const( vec, chan ) ); - /* Quick hack to multiply by 16 -- need to add SHL to rtasm. + /* Quick hack to multiply r1 by 16 -- need to add SHL to rtasm. */ x86_add( func, r1, r1 ); x86_add( func, r1, r1 ); x86_add( func, r1, r1 ); x86_add( func, r1, r1 ); - x86_add( func, r0, r1 ); + x86_add( func, r0, r1 ); /* r0 = r0 + r1 */ x86_mov( func, r1, x86_deref( r0 ) ); x86_mov( func, x86_make_disp( get_temp( TEMP_R0, CHAN_X ), i * 4 ), r1 ); } @@ -265,6 +293,7 @@ emit_const( get_temp( TEMP_R0, CHAN_X ) ); } else { + /* 'vec' is the index into the src register file, such as TEMP[vec] */ assert( vec >= 0 ); sse_movss( |