build: separate compiler and libs

compiler/internal/runtime/math/math.go

@@ -0,0 +1,36 @@
+package math
+
+import "github.com/goplus/llgo/compiler/internal/runtime/goarch"
+
+const MaxUintptr = ^uintptr(0)
+
+// MulUintptr returns a * b and whether the multiplication overflowed.
+// On supported platforms this is an intrinsic lowered by the compiler.
+func MulUintptr(a, b uintptr) (uintptr, bool) {
+	if a|b < 1<<(4*goarch.PtrSize) || a == 0 {
+		return a * b, false
+	}
+	overflow := b > MaxUintptr/a
+	return a * b, overflow
+}
+
+// Mul64 returns the 128-bit product of x and y: (hi, lo) = x * y
+// with the product bits' upper half returned in hi and the lower
+// half returned in lo.
+// This is a copy from math/bits.Mul64
+// On supported platforms this is an intrinsic lowered by the compiler.
+func Mul64(x, y uint64) (hi, lo uint64) {
+	const mask32 = 1<<32 - 1
+	x0 := x & mask32
+	x1 := x >> 32
+	y0 := y & mask32
+	y1 := y >> 32
+	w0 := x0 * y0
+	t := x1*y0 + w0>>32
+	w1 := t & mask32
+	w2 := t >> 32
+	w1 += x0 * y1
+	hi = x1*y1 + w2 + w1>>32
+	lo = x * y
+	return
+}