Factorial

main:
    ecall x10, x0, 5
    addi  sp, sp, 1600
    addi x20, x0, 1
    jal x1, fact

    # jal x0, exit
    beq x0, x0, exit

fact:
    addi    sp, sp, -16         # $t0 = $t1 + 0
    sd      x1, 8(sp)
    sd      x10, 0(sp)

    addi    x5, x10, 0
    bge     x5, x20, L1 #  # x >= 1

    addi    x10, x0, 1
    addi    sp, sp, 16
    jalr    x0, 0(x1)

L1:
    addi    x10, x10, -1
    jal     x1, fact

    addi    x6, x10, 0
    ld      x10, 0(sp)
    ld      x1, 8(sp)
    addi    sp, sp, 16
    mul     x10, x10, x6

    jalr    x0, 0(x1)


exit: