Only enable AVX512 on AMD64

Fixes #102

galois.go

@@ -852,6 +852,9 @@ func galMultiply(a, b byte) byte {
 	return mulTable[a][b]
 }
 
+// amd64 indicates whether we are on an amd64 platform.
+var amd64 bool
+
 // Original function:
 /*
 // galMultiply multiplies to elements of the field.

galoisAvx512_amd64.go

@@ -13,6 +13,10 @@ func _galMulAVX512Parallel82(in, out [][]byte, matrix *[matrixSize82]byte, addTo
 //go:noescape
 func _galMulAVX512Parallel84(in, out [][]byte, matrix *[matrixSize84]byte, addTo bool)
 
+func init() {
+	amd64 = true
+}
+
 const (
 	dimIn        = 8                            // Number of input rows processed simultaneously
 	dimOut82     = 2                            // Number of output rows processed simultaneously for x2 routine

options.go

@@ -31,7 +31,7 @@ func init() {
 	defaultOptions.useSSSE3 = cpuid.CPU.SSSE3()
 	defaultOptions.useSSE2 = cpuid.CPU.SSE2()
 	defaultOptions.useAVX2 = cpuid.CPU.AVX2()
-	defaultOptions.useAVX512 = cpuid.CPU.AVX512F() && cpuid.CPU.AVX512BW()
+	defaultOptions.useAVX512 = cpuid.CPU.AVX512F() && cpuid.CPU.AVX512BW() && amd64
 }
 
 // WithMaxGoroutines is the maximum number of goroutines number for encoding & decoding.