r600g: LIT: clamp negative src.y to 0

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=39083

Signed-off-by: Vadim Girlin <vadimgirlin@gmail.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index 6bb5ceb..2f07d59 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -1373,6 +1373,22 @@ static int tgsi_lit(struct r600_shader_ctx *ctx)
        struct r600_bc_alu alu;
        int r;
 
+       /* tmp.x = max(src.y, 0.0) */
+       memset(&alu, 0, sizeof(struct r600_bc_alu));
+       alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_MAX);
+       r600_bc_src(&alu.src[0], &ctx->src[0], 1);
+       alu.src[1].sel  = V_SQ_ALU_SRC_0; /*0.0*/
+       alu.src[1].chan = 1;
+
+       alu.dst.sel = ctx->temp_reg;
+       alu.dst.chan = 0;
+       alu.dst.write = 1;
+
+       alu.last = 1;
+       r = r600_bc_add_alu(ctx->bc, &alu);
+       if (r)
+               return r;
+
        if (inst->Dst[0].Register.WriteMask & (1 << 2))
        {
                int chan;
@@ -1381,11 +1397,13 @@ static int tgsi_lit(struct r600_shader_ctx *ctx)
 
                if (ctx->bc->chiprev == CHIPREV_CAYMAN) {
                        for (i = 0; i < 3; i++) {
-                               /* dst.z = log(src.y) */
+                               /* tmp.z = log(tmp.x) */
                                memset(&alu, 0, sizeof(struct r600_bc_alu));
                                alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_LOG_CLAMPED);
-                               r600_bc_src(&alu.src[0], &ctx->src[0], 1);
-                               tgsi_dst(ctx, &inst->Dst[0], i, &alu.dst);
+                               alu.src[0].sel = ctx->temp_reg;
+                               alu.src[0].chan = 0;
+                               alu.dst.sel = ctx->temp_reg;
+                               alu.dst.chan = i;
                                if (i == 2) {
                                        alu.dst.write = 1;
                                        alu.last = 1;
@@ -1397,10 +1415,11 @@ static int tgsi_lit(struct r600_shader_ctx *ctx)
                                        return r;
                        }
                } else {
-                       /* tmp.z = log(src.y) */
+                       /* tmp.z = log(tmp.x) */
                        memset(&alu, 0, sizeof(struct r600_bc_alu));
                        alu.inst = CTX_INST(V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_LOG_CLAMPED);
-                       r600_bc_src(&alu.src[0], &ctx->src[0], 1);
+                       alu.src[0].sel = ctx->temp_reg;
+                       alu.src[0].chan = 0;
                        alu.dst.sel = ctx->temp_reg;
                        alu.dst.chan = 2;
                        alu.dst.write = 1;