dawn-cmake/test/tint/builtins/gen/firstLeadingBit/3fd7d0.wgsl.expected.msl
Ben Clayton 8169693136 builtins: Add firstLeadingBit
Currently polyfilled for all backends.
HLSL should be able to map this to 'firstbithigh', but there might need
to be some special case handling for 0 (undocumented behavior). For now
just polyfill.

CTS tests: https://github.com/gpuweb/cts/pull/1004

Bug: tint:1367
Bug: tint:1449
Change-Id: I9c9a08ea93d1c4a602e0ab763e95e2eea336fb0d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/81503
Reviewed-by: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
2022-02-23 18:20:30 +00:00

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1.2 KiB
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#include <metal_stdlib>
using namespace metal;
uint3 tint_first_leading_bit(uint3 v) {
uint3 x = v;
uint3 const b16 = select(uint3(0u), uint3(16u), bool3((x & uint3(4294901760u))));
x = (x >> b16);
uint3 const b8 = select(uint3(0u), uint3(8u), bool3((x & uint3(65280u))));
x = (x >> b8);
uint3 const b4 = select(uint3(0u), uint3(4u), bool3((x & uint3(240u))));
x = (x >> b4);
uint3 const b2 = select(uint3(0u), uint3(2u), bool3((x & uint3(12u))));
x = (x >> b2);
uint3 const b1 = select(uint3(0u), uint3(1u), bool3((x & uint3(2u))));
uint3 const is_zero = select(uint3(0u), uint3(4294967295u), (x == uint3(0u)));
return uint3((((((b16 | b8) | b4) | b2) | b1) | is_zero));
}
void firstLeadingBit_3fd7d0() {
uint3 res = tint_first_leading_bit(uint3());
}
struct tint_symbol {
float4 value [[position]];
};
float4 vertex_main_inner() {
firstLeadingBit_3fd7d0();
return float4();
}
vertex tint_symbol vertex_main() {
float4 const inner_result = vertex_main_inner();
tint_symbol wrapper_result = {};
wrapper_result.value = inner_result;
return wrapper_result;
}
fragment void fragment_main() {
firstLeadingBit_3fd7d0();
return;
}
kernel void compute_main() {
firstLeadingBit_3fd7d0();
return;
}