r300/compiler: Implement ROUND

According to the GLSL spec, the implementor can decide which way to round
when the fraction is .5.  The r300 compiler will round down.

diff --git a/src/gallium/drivers/r300/compiler/radeon_opcodes.c b/src/gallium/drivers/r300/compiler/radeon_opcodes.c
index afd78ad..527db9a 100644 (file)
--- a/src/gallium/drivers/r300/compiler/radeon_opcodes.c
+++ b/src/gallium/drivers/r300/compiler/radeon_opcodes.c
@@ -246,6 +246,13 @@ struct rc_opcode_info rc_opcodes[MAX_RC_OPCODE] = {
                .IsStandardScalar = 1
        },
        {
+               .Opcode = RC_OPCODE_ROUND,
+               .Name = "ROUND",
+               .NumSrcRegs = 1,
+               .HasDstReg = 1,
+               .IsComponentwise = 1
+       },
+       {
                .Opcode = RC_OPCODE_RSQ,
                .Name = "RSQ",
                .NumSrcRegs = 1,

diff --git a/src/gallium/drivers/r300/compiler/radeon_opcodes.h b/src/gallium/drivers/r300/compiler/radeon_opcodes.h
index b586882..0b881c2 100644 (file)
--- a/src/gallium/drivers/r300/compiler/radeon_opcodes.h
+++ b/src/gallium/drivers/r300/compiler/radeon_opcodes.h
@@ -133,6 +133,9 @@ typedef enum {
        /** scalar instruction: dst = 1 / src0.x */
        RC_OPCODE_RCP,
 
+       /** vec4 instruction: dst.c = floor(src0.c + 0.5) */
+       RC_OPCODE_ROUND,
+
        /** scalar instruction: dst = 1 / sqrt(src0.x) */
        RC_OPCODE_RSQ,
 

diff --git a/src/gallium/drivers/r300/compiler/radeon_program_alu.c b/src/gallium/drivers/r300/compiler/radeon_program_alu.c
index e273bc4..dd1dfb3 100644 (file)
--- a/src/gallium/drivers/r300/compiler/radeon_program_alu.c
+++ b/src/gallium/drivers/r300/compiler/radeon_program_alu.c
@@ -104,6 +104,13 @@ static const struct rc_src_register builtin_one = {
        .Index = 0,
        .Swizzle = RC_SWIZZLE_1111
 };
+
+static const struct rc_src_register builtin_half = {
+       .File = RC_FILE_NONE,
+       .Index = 0,
+       .Swizzle = RC_SWIZZLE_HHHH
+};
+
 static const struct rc_src_register srcreg_undefined = {
        .File = RC_FILE_NONE,
        .Index = 0,
@@ -416,6 +423,43 @@ static void transform_POW(struct radeon_compiler* c,
        rc_remove_instruction(inst);
 }
 
+/* dst = ROUND(src) :
+ *   add = src + .5
+ *   frac = FRC(add)
+ *   dst = add - frac
+ *
+ * According to the GLSL spec, the implementor can decide which way to round
+ * when the fraction is .5.  We round down for .5.
+ *
+ */
+static void transform_ROUND(struct radeon_compiler* c,
+       struct rc_instruction* inst)
+{
+       unsigned int mask = inst->U.I.DstReg.WriteMask;
+       unsigned int frac_index, add_index;
+       struct rc_dst_register frac_dst, add_dst;
+       struct rc_src_register frac_src, add_src;
+
+       /* add = src + .5 */
+       add_index = rc_find_free_temporary(c);
+       add_dst = dstregtmpmask(add_index, mask);
+       emit2(c, inst->Prev, RC_OPCODE_ADD, 0, add_dst, inst->U.I.SrcReg[0],
+                                                               builtin_half);
+       add_src = srcreg(RC_FILE_TEMPORARY, add_dst.Index);
+
+
+       /* frac = FRC(add) */
+       frac_index = rc_find_free_temporary(c);
+       frac_dst = dstregtmpmask(frac_index, mask);
+       emit1(c, inst->Prev, RC_OPCODE_FRC, 0, frac_dst, add_src);
+       frac_src = srcreg(RC_FILE_TEMPORARY, frac_dst.Index);
+
+       /* dst = add - frac */
+       emit2(c, inst->Prev, RC_OPCODE_ADD, 0, inst->U.I.DstReg,
+                                               add_src, negate(frac_src));
+       rc_remove_instruction(inst);
+}
+
 static void transform_RSQ(struct radeon_compiler* c,
        struct rc_instruction* inst)
 {
@@ -599,6 +643,7 @@ int radeonTransformALU(
        case RC_OPCODE_LIT: transform_LIT(c, inst); return 1;
        case RC_OPCODE_LRP: transform_LRP(c, inst); return 1;
        case RC_OPCODE_POW: transform_POW(c, inst); return 1;
+       case RC_OPCODE_ROUND: transform_ROUND(c, inst); return 1;
        case RC_OPCODE_RSQ: transform_RSQ(c, inst); return 1;
        case RC_OPCODE_SEQ: transform_SEQ(c, inst); return 1;
        case RC_OPCODE_SFL: transform_SFL(c, inst); return 1;

diff --git a/src/gallium/drivers/r300/r300_tgsi_to_rc.c b/src/gallium/drivers/r300/r300_tgsi_to_rc.c
index 07a3f3c..4cb08b5 100644 (file)
--- a/src/gallium/drivers/r300/r300_tgsi_to_rc.c
+++ b/src/gallium/drivers/r300/r300_tgsi_to_rc.c
@@ -57,7 +57,7 @@ static unsigned translate_opcode(unsigned opcode)
         case TGSI_OPCODE_FRC: return RC_OPCODE_FRC;
         case TGSI_OPCODE_CLAMP: return RC_OPCODE_CLAMP;
         case TGSI_OPCODE_FLR: return RC_OPCODE_FLR;
-     /* case TGSI_OPCODE_ROUND: return RC_OPCODE_ROUND; */
+        case TGSI_OPCODE_ROUND: return RC_OPCODE_ROUND;
         case TGSI_OPCODE_EX2: return RC_OPCODE_EX2;
         case TGSI_OPCODE_LG2: return RC_OPCODE_LG2;
         case TGSI_OPCODE_POW: return RC_OPCODE_POW;