examples/fibonacci.hdass


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[entry: main]

const SYS_WRITE = 1
const SYS_EXIT = 60

const STDOUT = 1

data newline = "\n"

proc print_number(value: rdi)
{
    stack buffer[32]

    rax = value
    rbx = 10
    rsi = buffer+31

convert:
    rdx = 0
    rax /= rbx
    rdx += '0'

    ^byte rsi = rdx
    rsi -= 1

    if rax != 0
        goto convert
    rsi += 1

    rax = SYS_WRITE
    rdi = STDOUT
    rdx = buffer+32-rsi
    syscall

    rax = SYS_WRITE
    rdi = STDOUT
    rsi = newline
    rdx = newline.len
    syscall
}

proc main
{
    r12 = 0
    r13 = 1
    r15 = 10      // syscall clobbers rcx/r11, so keep the counter in r15

loop:
    print_number(r12)

    rax = r12
    r12 = r13
    r13 += rax

    r15 -= 1
    if r15 != 0
        goto loop

    rax = SYS_EXIT
    rdi = 0
    syscall
}