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r300/compiler: Fix vertex program MAD emit

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Only use the macro variant of MAD when absolutely necessary.
Apparently it cannot deal with relative addressing.

Signed-off-by: Nicolai Hähnle <nhaehnle@gmail.com>
This commit is contained in:
Nicolai Hähnle
2009-08-26 23:31:37 +02:00
parent 2114acb044
commit c024f1047f
1 changed files with 46 additions and 6 deletions
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52
src/mesa/drivers/dri/r300/compiler/r3xx_vertprog.c
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@@ -284,12 +284,52 @@ static void ei_mad(struct r300_vertex_program_code *vp,
struct prog_instruction *vpi,
GLuint * inst)
{
inst[0] = PVS_OP_DST_OPERAND(PVS_MACRO_OP_2CLK_MADD,
GL_FALSE,
GL_TRUE,
t_dst_index(vp, &vpi->DstReg),
t_dst_mask(vpi->DstReg.WriteMask),
t_dst_class(vpi->DstReg.File));
/* Remarks about hardware limitations of MAD
* (please preserve this comment, as this information is _NOT_
* in the documentation provided by AMD).
*
* As described in the documentation, MAD with three unique temporary
* source registers requires the use of the macro version.
*
* However (and this is not mentioned in the documentation), apparently
* the macro version is _NOT_ a full superset of the normal version.
* In particular, the macro version does not always work when relative
* addressing is used in the source operands.
*
* This limitation caused incorrect rendering in Sauerbraten's OpenGL
* assembly shader path when using medium quality animations
* (i.e. animations with matrix blending instead of quaternion blending).
*
* Unfortunately, I (nha) have been unable to extract a Piglit regression
* test for this issue - for some reason, it is possible to have vertex
* programs whose prefix is *exactly* the same as the prefix of the
* offending program in Sauerbraten up to the offending instruction
* without causing any trouble.
*
* Bottom line: Only use the macro version only when really necessary;
* according to AMD docs, this should improve performance by one clock
* as a nice side bonus.
*/
if (vpi->SrcReg[0].File == PROGRAM_TEMPORARY &&
vpi->SrcReg[1].File == PROGRAM_TEMPORARY &&
vpi->SrcReg[2].File == PROGRAM_TEMPORARY &&
vpi->SrcReg[0].Index != vpi->SrcReg[1].Index &&
vpi->SrcReg[0].Index != vpi->SrcReg[2].Index &&
vpi->SrcReg[1].Index != vpi->SrcReg[2].Index) {
inst[0] = PVS_OP_DST_OPERAND(PVS_MACRO_OP_2CLK_MADD,
GL_FALSE,
GL_TRUE,
t_dst_index(vp, &vpi->DstReg),
t_dst_mask(vpi->DstReg.WriteMask),
t_dst_class(vpi->DstReg.File));
} else {
inst[0] = PVS_OP_DST_OPERAND(VE_MULTIPLY_ADD,
GL_FALSE,
GL_FALSE,
t_dst_index(vp, &vpi->DstReg),
t_dst_mask(vpi->DstReg.WriteMask),
t_dst_class(vpi->DstReg.File));
}
inst[1] = t_src(vp, &vpi->SrcReg[0]);
inst[2] = t_src(vp, &vpi->SrcReg[1]);
inst[3] = t_src(vp, &vpi->SrcReg[2]);