Untitled

extern printf ; the C function to be called
%macro pabc 1 ; a "simple" print macro
section .data
.str db %1,0 ; %1 is first actual in macro call
section .text
; push onto stack backwards
push dword [c] ; int c
push dword [b] ; int b
push dword [a] ; int a
push dword .str ; users string
 push dword fmt ; address of format string
 call printf ; Call C function
 add esp,20 ; pop stack 5*4 bytes
%endmacro
section .data ; preset constants, writeable
a: dd 3 ; 32-bit variable a initialized to 3
b: dd 4 ; 32-bit variable b initializes to 4
fmt: db "%s, a=%d, b=%d, c=%d",10,0 ; format string for printf
section .bss ; unitialized space
c: resd 1 ; reserve a 32-bit word
section .text ; instructions, code segment
global main ; for gcc standard linking
main: ; label
lit5: ; c=5;
mov eax,5 ; 5 is a literal constant
mov [c],eax ; store into c
pabc "c=5 " ; invoke the print macro
addb: ; c=a+b;
mov eax,[a] ; load a
add eax,[b] ; add b
mov [c],eax ; store into c
pabc "c=a+b" ; invoke the print macro
subb: ; c=a-b;
mov eax,[a] ; load a
sub eax,[b] ; subtract b
mov [c],eax ; store into c
pabc "c=a-b" ; invoke the print macro
mulb: ; c=a*b;
mov eax,[a] ; load a (must be eax for multiply)
imul dword [b] ; signed integer multiply by b
mov [c],eax ; store bottom half of product into c
pabc "c=a*b" ; invoke the print macro
diva: ; c=c/a;
mov eax,[c] ; load c
mov edx,0 ; load upper half of dividend with zero
idiv dword [a] ; divide double register edx eax by a
mov [c],eax ; store quotient into c
pabc "c=c/a" ; invoke the print macro
 mov eax,0 ; exit code, 0=normal
ret ; main return to operating system