Giovanni Mascellani : vkd3d-shader: Convert write masks between 32 and 64 bit by cases.

[Alexandre Julliard]

Module: vkd3d
Branch: master
Commit: 2b93aae069c9b6920db08d3fe4a7f68f18671946
URL:    https://gitlab.winehq.org/wine/vkd3d/-/commit/2b93aae069c9b6920db08d3fe4a7f6...

Author: Giovanni Mascellani 
Date:   Sat Jan 20 23:30:23 2024 +0100

vkd3d-shader: Convert write masks between 32 and 64 bit by cases.

There are only three cases, and while the code is longer it is also
hopefully easier to read. Moreover, an error message is casted if
we're doing something unexpected.

---

libs/vkd3d-shader/vkd3d_shader_private.h | 35 +++++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)

diff --git a/libs/vkd3d-shader/vkd3d_shader_private.h b/libs/vkd3d-shader/vkd3d_shader_private.h
index f8c4d61e..cbac998a 100644
--- a/libs/vkd3d-shader/vkd3d_shader_private.h
+++ b/libs/vkd3d-shader/vkd3d_shader_private.h
@@ -1605,15 +1605,40 @@ static inline unsigned int vkd3d_write_mask_from_component_count(unsigned int co

static inline uint32_t vsir_write_mask_64_from_32(uint32_t write_mask32)
 {
-    uint32_t write_mask64 = write_mask32 | (write_mask32 >> 1);
-    return (write_mask64 & VKD3DSP_WRITEMASK_0) | ((write_mask64 & VKD3DSP_WRITEMASK_2) >> 1);
+    switch (write_mask32)
+    {
+        case VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_1:
+            return VKD3DSP_WRITEMASK_0;
+
+        case VKD3DSP_WRITEMASK_2 | VKD3DSP_WRITEMASK_3:
+            return VKD3DSP_WRITEMASK_1;
+
+        case VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_1 | VKD3DSP_WRITEMASK_2 | VKD3DSP_WRITEMASK_3:
+            return VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_1;
+
+        default:
+            ERR("Invalid 32 bit writemask when converting to 64 bit: %#x.\n", write_mask32);
+            return VKD3DSP_WRITEMASK_0;
+    }
 }

static inline uint32_t vsir_write_mask_32_from_64(uint32_t write_mask64)
 {
-    uint32_t write_mask32 = (write_mask64 | (write_mask64 << 1))
-            & (VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_2);
-    return write_mask32 | (write_mask32 << 1);
+    switch (write_mask64)
+    {
+        case VKD3DSP_WRITEMASK_0:
+            return VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_1;
+
+        case VKD3DSP_WRITEMASK_1:
+            return VKD3DSP_WRITEMASK_2 | VKD3DSP_WRITEMASK_3;
+
+        case VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_1:
+            return VKD3DSP_WRITEMASK_0 | VKD3DSP_WRITEMASK_1 | VKD3DSP_WRITEMASK_2 | VKD3DSP_WRITEMASK_3;
+
+        default:
+            ERR("Invalid 64 bit writemask: %#x.\n", write_mask64);
+            return VKD3DSP_WRITEMASK_0;
+    }
 }

static inline unsigned int vsir_swizzle_get_component(uint32_t swizzle, unsigned int idx)