!= len(y) { panic("subtle: slices have different lengths") } xmask := byte(v - 1) ymask := byte(^(v - 1)) for i := 0; i < len(x); i++ { x[i] = x[i]&xmask | y[i]&ymask } } // ConstantTimeLessOrEq returns 1 if x <= y and 0 otherwise. // Its behavior is undefined if x or y are negative or > 2**31 - 1. func ConstantTimeLessOrEq(x, y int) int { x32 := int32(x) y32 := int32(y) return int(((x32 - y32 - 1) >> 31) & 1) } golang.org/fips140@v1.0.0/fips140/v1.0.0/subtle/xor.go // Copyright 2022 The Go Authors....