radeonsi: implement GL_FIXED vertex format

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 840b379..f404273 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -492,18 +492,28 @@
 		break;
 	case SI_FIX_FETCH_RGBA_32_SNORM:
 	case SI_FIX_FETCH_RGBX_32_SNORM:
+	case SI_FIX_FETCH_RGBA_32_FIXED:
+	case SI_FIX_FETCH_RGBX_32_FIXED: {
+		double scale;
+		if (fix_fetch >= SI_FIX_FETCH_RGBA_32_FIXED)
+			scale = 1.0 / 0x10000;
+		else
+			scale = 1.0 / INT_MAX;
+
 		for (chan = 0; chan < 4; chan++) {
 			out[chan] = LLVMBuildBitCast(gallivm->builder, out[chan],
 						     ctx->i32, "");
 			out[chan] = LLVMBuildSIToFP(gallivm->builder,
 						    out[chan], ctx->f32, "");
 			out[chan] = LLVMBuildFMul(gallivm->builder, out[chan],
-						  LLVMConstReal(ctx->f32, 1.0 / INT_MAX), "");
+						  LLVMConstReal(ctx->f32, scale), "");
 		}
 		/* RGBX SINT returns 1 in alpha, which would be rounded to 0 by normalizing. */
-		if (fix_fetch == SI_FIX_FETCH_RGBX_32_SNORM)
+		if (fix_fetch == SI_FIX_FETCH_RGBX_32_SNORM ||
+		    fix_fetch == SI_FIX_FETCH_RGBX_32_FIXED)
 			out[3] = LLVMConstReal(ctx->f32, 1);
 		break;
+	}
 	case SI_FIX_FETCH_RGBA_32_USCALED:
 		for (chan = 0; chan < 4; chan++) {
 			out[chan] = LLVMBuildBitCast(gallivm->builder, out[chan],
diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index 5e554d9..7584035 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -245,6 +245,8 @@
 	SI_FIX_FETCH_RGBX_32_SNORM,
 	SI_FIX_FETCH_RGBA_32_USCALED,
 	SI_FIX_FETCH_RGBA_32_SSCALED,
+	SI_FIX_FETCH_RGBA_32_FIXED,
+	SI_FIX_FETCH_RGBX_32_FIXED,
 };
 
 struct si_shader;
diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
index c8d1099..865a75d 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -1697,17 +1697,12 @@
 					       const struct util_format_description *desc,
 					       int first_non_void)
 {
-	unsigned type;
 	int i;
 
 	if (desc->format == PIPE_FORMAT_R11G11B10_FLOAT)
 		return V_008F0C_BUF_DATA_FORMAT_10_11_11;
 
 	assert(first_non_void >= 0);
-	type = desc->channel[first_non_void].type;
-
-	if (type == UTIL_FORMAT_TYPE_FIXED)
-		return V_008F0C_BUF_DATA_FORMAT_INVALID;
 
 	if (desc->nr_channels == 4 &&
 	    desc->channel[0].size == 10 &&
@@ -1773,6 +1768,7 @@
 
 	switch (desc->channel[first_non_void].type) {
 	case UTIL_FORMAT_TYPE_SIGNED:
+	case UTIL_FORMAT_TYPE_FIXED:
 		if (desc->channel[first_non_void].size >= 32 ||
 		    desc->channel[first_non_void].pure_integer)
 			return V_008F0C_BUF_NUM_FORMAT_SINT;
@@ -3366,6 +3362,11 @@
 				/* This isn't actually used in OpenGL. */
 				v->fix_fetch |= (uint64_t)SI_FIX_FETCH_A2_SINT << (4 * i);
 			}
+		} else if (channel->type == UTIL_FORMAT_TYPE_FIXED) {
+			if (desc->swizzle[3] == PIPE_SWIZZLE_1)
+				v->fix_fetch |= (uint64_t)SI_FIX_FETCH_RGBX_32_FIXED << (4 * i);
+			else
+				v->fix_fetch |= (uint64_t)SI_FIX_FETCH_RGBA_32_FIXED << (4 * i);
 		} else if (channel->size == 32 && !channel->pure_integer) {
 			if (channel->type == UTIL_FORMAT_TYPE_SIGNED) {
 				if (channel->normalized) {