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26bb81f3f6
This expression accidentally performs a 32-bit sign-extension when
processing the second half of the expression (the low 16 bits).
Consider -7W, which is represented as 0xfff9fff9 in our encoding (the
16-bit word is replicated to both halves of the 32-bit dword).
Tigerlake's compaction stores the low 11-bits of an immediate as-is,
and replicates the 12th bit. So here, compacted_imm will be 0xff9.
( (int)(0xff9 << 20) >> 4) |
((short)(0xff9 << 4) >> 4))
0xfff90000 | (0xff90 >> 4)
0xfff90000 | 0xfffffff9 ...oops...
0xfffffff9
By casting the second line of the expression to unsigned short, we
prevent the sign-extension when it combines both parts, so we get:
0xfff90000 | 0x0000fff9
0xfff9fff9
Fixes:
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|---|---|---|
| .. | ||
| amd | ||
| android_stub | ||
| asahi | ||
| broadcom | ||
| compiler | ||
| drm-shim | ||
| egl | ||
| etnaviv | ||
| freedreno | ||
| gallium | ||
| gbm | ||
| getopt | ||
| glx | ||
| gtest | ||
| hgl | ||
| imagination | ||
| imgui | ||
| intel | ||
| loader | ||
| mapi | ||
| mesa | ||
| microsoft | ||
| nouveau | ||
| panfrost | ||
| tool | ||
| util | ||
| virtio | ||
| vulkan | ||
| meson.build | ||