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silicon_sse: naked FMA asm for vec3Dot (0.4x->0.8x) and distanceToPlane (0.7x->1.0x)

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This commit is contained in:
MarcelineVQ
2026-03-17 01:01:07 -07:00
parent 9488fb568c
commit cb0888e0fa
2 changed files with 84 additions and 29 deletions
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src/bench/main.zig
+31 -12
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@@ -35,7 +35,7 @@ extern fn si_normalizeVec3(u32, u32) void;
extern fn si_mulMat3x4(u32, u32, u32) u32;
extern fn si_rotateMatByQuat(u32, u32) u32;
extern fn si_createRotMat3x4(u32, u32, u32, u32) u32;
extern fn si_distanceToPlane(u32, u32, u32) f64;
extern fn si_distanceToPlane() callconv(.naked) void; // naked: ECX=point, EDX=plane, stack=dir, returns ST(0), RET 4
extern fn si_classifyPointFrustum(u32, u32, u32) u32;
extern fn si_checkBoxLineIntersect(u32, u32, u32) u32;
extern fn si_testOBBFrustum(u32, u32, u32, u32) u32;
@@ -47,7 +47,7 @@ extern fn si_createZRotMat3x3(u32, u32) u32;
extern fn si_transposeMat4x4(u32, u32) u32;
extern fn si_mulMat3x4InPlace(u32, u32) u32;
extern fn si_normalizeVec3InPlace(u32) void;
extern fn si_vec3Dot(u32, u32) f64;
extern fn si_vec3Dot() callconv(.naked) void; // naked: ECX=a, EDX=b, returns ST(0)
extern fn si_translateBoundingVol(u32, u32) void;
extern fn si_addVec3ToAccumulator(u32, u32, u32) void;
extern fn si_addToColorAccumulator(u32, u32) void;
@@ -477,16 +477,32 @@ pub fn main() void {
report("isPointInsideBounds", t, s, ok);
}
// si_vec3Dot (31K/7.5s) -- fastcall(vecA_ECX, vecB_EDX) -> f64
// si_vec3Dot (31K/7.5s) -- fastcall(vecA_ECX, vecB_EDX) -> ST(0)
// Both original and SSE are naked/fastcall, call via asm
{
const va2 = tv3();
const vb2 = tv3b();
const of = origFn(fn (u32, u32) callconv(cc_fc) f64, 0x602630);
const ov = of(a(&va2), a(&vb2));
const sv = si_vec3Dot(a(&va2), a(&vb2));
const callDot = struct {
fn call(func: u32, va_ptr: u32, vb_ptr: u32) f64 {
var result: f64 = undefined;
var eax_trash: u32 = undefined;
asm volatile (
\\call *%[func]
\\fstpl (%[out])
: [eax_out] "={eax}" (eax_trash),
: [func] "r" (func),
[out] "r" (&result),
[_ecx] "{ecx}" (va_ptr),
[_edx] "{edx}" (vb_ptr),
);
return result;
}
}.call;
const ov = callDot(0x602630, a(&va2), a(&vb2));
const sv = callDot(@intFromPtr(&si_vec3Dot), a(&va2), a(&vb2));
const ok = @abs(ov - sv) < 1e-4;
var t = rdtsc(); for (0..ITERS) |_| { _ = of(a(&va2), a(&vb2)); } t = rdtsc() - t;
var s = rdtsc(); for (0..ITERS) |_| { _ = si_vec3Dot(a(&va2), a(&vb2)); } s = rdtsc() - s;
var t = rdtsc(); for (0..ITERS) |_| { _ = callDot(0x602630, a(&va2), a(&vb2)); } t = rdtsc() - t;
var s = rdtsc(); for (0..ITERS) |_| { _ = callDot(@intFromPtr(&si_vec3Dot), a(&va2), a(&vb2)); } s = rdtsc() - s;
report("si_vec3Dot", t, s, ok);
}
@@ -503,17 +519,20 @@ pub fn main() void {
report("normalizeVec3InPlace", t, s, ok);
}
// si_distanceToPlane (525K/7.5s) -- fastcall(point_ECX, plane_EDX, dir_stack) -> f64
// si_distanceToPlane (525K/7.5s) -- fastcall(point_ECX, plane_EDX, dir_stack) -> ST(0), RET 4
// Both original and SSE version use same CC — call via function pointer cast
{
const pt = tv3();
const plane = [4]f32{ 0.0, 1.0, 0.0, -5.0 }; // y=5 plane
const dir = Vec3{ 0.0, -1.0, 0.0 }; // pointing down
const of: *const fn (u32, u32, u32) callconv(cc_fc) f64 = origFn(fn (u32, u32, u32) callconv(cc_fc) f64, 0x6329E0);
const FnType = fn (u32, u32, u32) callconv(cc_fc) f64;
const of: *const FnType = origFn(FnType, 0x6329E0);
const sf: *const FnType = @ptrCast(&si_distanceToPlane);
const ov = of(a(&pt), a(&plane), a(&dir));
const sv = si_distanceToPlane(a(&pt), a(&plane), a(&dir));
const sv = sf(a(&pt), a(&plane), a(&dir));
const ok = @abs(ov - sv) < 1e-2;
var t = rdtsc(); for (0..ITERS) |_| { _ = of(a(&pt), a(&plane), a(&dir)); } t = rdtsc() - t;
var s = rdtsc(); for (0..ITERS) |_| { _ = si_distanceToPlane(a(&pt), a(&plane), a(&dir)); } s = rdtsc() - s;
var s = rdtsc(); for (0..ITERS) |_| { _ = sf(a(&pt), a(&plane), a(&dir)); } s = rdtsc() - s;
report("distanceToPlane", t, s, ok);
}