sum
Sum a slice of uint64s.
func main() {
TEXT("Sum", "func(xs []uint64) uint64")
Doc("Sum returns the sum of the elements in xs.")
ptr := Load(Param("xs").Base(), GP64())
n := Load(Param("xs").Len(), GP64())
s := GP64()
XORQ(s, s)
LABEL("loop")
CMPQ(n, operand.Imm(0))
JE(operand.LabelRef("done"))
ADDQ(operand.Mem{Base: ptr}, s)
ADDQ(operand.Imm(8), ptr)
DECQ(n)
JMP(operand.LabelRef("loop"))
LABEL("done")
Store(s, ReturnIndex(0))
RET()
Generate()
}