asm

scripts/asm

@@ -0,0 +1,8 @@
+#!/bin/sh
+set -e
+
+bash ./scripts/prepare.sh
+
+nasm -f elf64 -o build/fb.o src/fb.asm
+gcc -no-pie -o  bin/fb_asm build/fb.o -lc
+bin/fb_asm

scripts/prepare.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+mkdir -p bin build

src/fb.asm

@@ -0,0 +1,115 @@
+	;    use the build-linux.sh script to assemble and link this
+	bits 64
+
+	section .note.GNU-stack
+
+	section .text
+
+	default rel; idk what this means?
+	global  main
+	extern  printf
+	extern  exit
+	align   16
+
+	%macro check 2
+	mov    rax, [rsp]
+	mov    rbx, %1
+	mov    rdx, 0
+	div    rbx; dividend is rax. rdx has remainder and rax has the quotient
+	cmp    rdx, 0
+	je     %2
+	%endmacro
+
+main:
+	enter 16, 0
+
+	mov rcx, 1; iterator
+	mov rbx, 0; temp var
+	mov rax, 0; temp var
+
+	push rcx; save iter on stack
+
+.loop:
+	;     show iteration
+	;mov  rax, [rsp]; read iter from stack
+	;call piter
+
+	check 15, .hboth
+	check 3, .hfizz
+	check 5, .hbuzz
+	;     else
+	jmp   .hpnum
+
+.hboth:
+	call fizz
+	call buzz
+	call nl
+	jmp  .loopend
+
+.hfizz:
+	call fizz
+	call nl
+	jmp  .loopend
+
+.hbuzz:
+	call buzz
+	call nl
+	jmp  .loopend
+
+.hpnum:
+	mov  rax, [rsp]
+	call pnum
+	jmp  .loopend
+
+.loopend:
+	pop  rcx
+	inc  rcx
+	push rcx
+	cmp  rcx, 100
+	jle  .loop
+	;    end of loop
+
+.end:
+	leave
+	call exit
+
+fizz:
+	mov  rdi, Lfizz
+	call printf
+	ret
+
+buzz:
+	mov  rdi, Lbuzz
+	call printf
+	ret
+
+nl:
+	mov  rdi, Lnl
+	call printf
+	ret
+
+pnum:
+	;    see https: // www.mourtada.se/calling-printf-from-the-c-standard-library-in-assembly/
+	mov  rdi, Lnumf
+	mov  rsi, rax
+	mov  rax, 0
+	call printf
+	ret
+
+section .rodata
+
+Lfizz:
+	db   "Fizz", 0
+	.len equ $ - Lfizz
+
+Lbuzz:
+	db   "Buzz", 0
+	.len equ $ - Lbuzz
+
+Lnl:
+	db   0x0a, 0
+	.len equ $ - Lnl
+
+Lnumf:
+	db   "%d", 10, 0
+	.len equ $ - Lnumf

src/fb.py

@@ -1,9 +1,9 @@
 for i in range(1,101):
     if i % 15 == 0 :
         print("FizzBuzz")
-    elif i % 5 == 0 :
-        print("Fizz")
     elif i % 3 == 0 :
+        print("Fizz")
+    elif i % 5 == 0 :
         print("Buzz")
     else:
         print(i)