Was previously implemented with FLOOR.
Fixes quite a few piglit tests of float->int conversion, integer
division, etc.
---
src/gallium/drivers/svga/svga_tgsi_insn.c | 56 ++++++++++++++++++++++++++++-
1 files changed, 55 insertions(+), 1 deletions(-)
diff --git a/src/gallium/drivers/svga/svga_tgsi_insn.c
b/src/gallium/drivers/svga/svga_tgsi_insn.c
index 64dfa55..678f38b 100644
--- a/src/gallium/drivers/svga/svga_tgsi_insn.c
+++ b/src/gallium/drivers/svga/svga_tgsi_insn.c
@@ -2374,6 +2374,57 @@ static boolean emit_log(struct svga_shader_emitter *emit,
}
+/**
+ * Translate TGSI TRUNC instruction.
+ * We need to truncate toward zero. Ex: trunc(-1.9) = -1
+ * Different approaches are needed for VS versus PS.
+ */
+static boolean
+emit_trunc(struct svga_shader_emitter *emit,
+ const struct tgsi_full_instruction *insn)
+{
+ SVGA3dShaderDestToken dst = translate_dst_register(emit, insn, 0);
+ const struct src_register src0 =
+ translate_src_register(emit, &insn->Src[0] );
+ SVGA3dShaderDestToken t1 = get_temp(emit);
+ SVGA3dShaderDestToken t2 = get_temp(emit);
+
+ /* t1 = fract(abs(src0)) */
+ if (!submit_op1(emit, inst_token(SVGA3DOP_FRC), t1, absolute(src0)))
+ return FALSE;
+
+ /* t1 = abs(src0) - t1 */
+ if (!submit_op2(emit, inst_token(SVGA3DOP_ADD), t1, absolute(src0),
+ negate(src(t1))))
+ return FALSE;
+
+ /*
+ * Now we need to multiply t1 by the sign of the original value.
+ */
+ if (emit->unit == PIPE_SHADER_VERTEX) {
+ /* For VS: use SGN instruction */
+ /* Need two extra/dummy registers: */
+ SVGA3dShaderDestToken t3 = get_temp(emit), t4 = get_temp(emit);
+
+ /* t2 = sign(src0) */
+ if (!submit_op3(emit, inst_token(SVGA3DOP_SGN), t2, src0,
+ src(t3), src(t4)))
+ return FALSE;
+
+ /* dst = t1 * t2 */
+ if (!submit_op2(emit, inst_token(SVGA3DOP_MUL), dst, src(t1), src(t2)))
+ return FALSE;
+ }
+ else {
+ /* For FS: Use CMP instruction */
+ return submit_op3(emit, inst_token( SVGA3DOP_CMP ), dst,
+ src0, src(t1), negate(src(t1)));
+ }
+
+ return TRUE;
+}
+
+
static boolean emit_bgnsub( struct svga_shader_emitter *emit,
unsigned position,
const struct tgsi_full_instruction *insn )
@@ -2464,9 +2515,11 @@ static boolean svga_emit_instruction( struct
svga_shader_emitter *emit,
return emit_call( emit, insn );
case TGSI_OPCODE_FLR:
- case TGSI_OPCODE_TRUNC: /* should be TRUNC, not FLR */
return emit_floor( emit, insn );
+ case TGSI_OPCODE_TRUNC:
+ return emit_trunc( emit, insn );
+
case TGSI_OPCODE_CEIL:
return emit_ceil( emit, insn );
@@ -3022,6 +3075,7 @@ needs_to_create_zero( struct svga_shader_emitter *emit )
if (emit->info.opcode_count[TGSI_OPCODE_DST] >= 1 ||
emit->info.opcode_count[TGSI_OPCODE_SSG] >= 1 ||
+ emit->info.opcode_count[TGSI_OPCODE_TRUNC] >= 1 ||
emit->info.opcode_count[TGSI_OPCODE_LIT] >= 1)
return TRUE;
--
1.7.3.4
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