mleku
14dc85cdc3
- Port field operations assembler from libsecp256k1 (field_amd64.s,
field_amd64_bmi2.s) with MULX/ADCX/ADOX instructions
- Add AVX2 scalar and affine point operations in avx/ package
- Implement CPU feature detection (cpufeatures.go) for AVX2/BMI2
- Add libsecp256k1.so via purego for native C library comparison
- Create comprehensive SIMD benchmark suite comparing btcec, P256K1
pure Go, P256K1 ASM, and libsecp256k1
- Add BENCHMARK_SIMD.md documenting performance across implementations
- Remove BtcecSigner, consolidate on P256K1Signer as primary impl
- Add field operation tests and benchmarks (field_asm_test.go,
field_bench_test.go)
- Update GLV endomorphism with wNAF scalar multiplication
- Add scalar assembly (scalar_amd64.s) for optimized operations
- Clean up dependencies and update benchmark reports
106 lines
3.0 KiB
Go
106 lines
3.0 KiB
Go
//go:build amd64
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package p256k1
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import (
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"sync"
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"sync/atomic"
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"github.com/klauspost/cpuid/v2"
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)
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// CPU feature flags
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var (
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// hasAVX2CPU indicates whether the CPU supports AVX2 instructions.
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// This is detected at startup and never changes.
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hasAVX2CPU bool
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// hasBMI2CPU indicates whether the CPU supports BMI2 instructions.
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// BMI2 provides MULX, ADCX, ADOX for efficient carry-chain arithmetic.
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hasBMI2CPU bool
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// hasADXCPU indicates whether the CPU supports ADX instructions.
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// ADX provides ADCX/ADOX for parallel carry chains.
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hasADXCPU bool
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// avx2Disabled allows runtime disabling of AVX2 for testing/debugging.
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// Uses atomic operations for thread-safety without locks on the fast path.
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avx2Disabled atomic.Bool
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// bmi2Disabled allows runtime disabling of BMI2 for testing/debugging.
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bmi2Disabled atomic.Bool
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// initOnce ensures CPU detection runs exactly once
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initOnce sync.Once
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)
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func init() {
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initOnce.Do(detectCPUFeatures)
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}
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// detectCPUFeatures detects CPU capabilities at startup
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func detectCPUFeatures() {
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hasAVX2CPU = cpuid.CPU.Has(cpuid.AVX2)
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hasBMI2CPU = cpuid.CPU.Has(cpuid.BMI2)
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hasADXCPU = cpuid.CPU.Has(cpuid.ADX)
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}
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// HasAVX2 returns true if AVX2 is available and enabled.
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// This is the function that should be called in hot paths to decide
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// whether to use AVX2-optimized code paths.
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func HasAVX2() bool {
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return hasAVX2CPU && !avx2Disabled.Load()
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}
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// HasAVX2CPU returns true if the CPU supports AVX2, regardless of whether
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// it's been disabled via SetAVX2Enabled.
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func HasAVX2CPU() bool {
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return hasAVX2CPU
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}
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// SetAVX2Enabled enables or disables the use of AVX2 instructions.
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// This is useful for benchmarking to compare AVX2 vs non-AVX2 performance,
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// or for debugging. Pass true to enable AVX2 (default), false to disable.
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// This function is thread-safe.
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func SetAVX2Enabled(enabled bool) {
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avx2Disabled.Store(!enabled)
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}
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// IsAVX2Enabled returns whether AVX2 is currently enabled.
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// Returns true if AVX2 is both available on the CPU and not disabled.
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func IsAVX2Enabled() bool {
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return HasAVX2()
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}
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// HasBMI2 returns true if BMI2 is available and enabled.
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// BMI2 provides MULX for efficient multiplication without affecting flags,
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// enabling parallel carry chains with ADCX/ADOX.
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func HasBMI2() bool {
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return hasBMI2CPU && hasADXCPU && !bmi2Disabled.Load()
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}
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// HasBMI2CPU returns true if the CPU supports BMI2, regardless of whether
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// it's been disabled via SetBMI2Enabled.
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func HasBMI2CPU() bool {
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return hasBMI2CPU
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}
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// HasADXCPU returns true if the CPU supports ADX (ADCX/ADOX instructions).
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func HasADXCPU() bool {
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return hasADXCPU
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}
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// SetBMI2Enabled enables or disables the use of BMI2 instructions.
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// This is useful for benchmarking to compare BMI2 vs non-BMI2 performance.
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// Pass true to enable BMI2 (default), false to disable.
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// This function is thread-safe.
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func SetBMI2Enabled(enabled bool) {
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bmi2Disabled.Store(!enabled)
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}
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// IsBMI2Enabled returns whether BMI2 is currently enabled.
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// Returns true if BMI2+ADX are both available on the CPU and not disabled.
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func IsBMI2Enabled() bool {
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return HasBMI2()
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}
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