Assembly x64 Intro - Logic Operate

; intlogic_64.asm    show some simple C code and corresponding nasm code
;                    the nasm code is one sample, not unique
;
; compile: nasm -f elf64 -l intlogic_64.lst  intlogic_64.asm
; link:  gcc -m64 -o intlogic_64  intlogic_64.o
; run:  ./intlogic_64 > intlogic_64.out
;
; the output from running intlogic_64.asm and intlogic.c is
; c=5  , a=3, b=5, c=15
; c=a&b, a=3, b=5, c=1
; c=a|b, a=3, b=5, c=7
; c=a^b, a=3, b=5, c=6
; c=~a , a=3, b=5, c=-4
;
;The file  intlogic_64.c  is:
;  #include <stdio.h>
;  int main()
;  {
;    long int a=3, b=5, c;
;
;    c=15;
;    printf("%s, a=%ld, b=%ld, c=%ld\n","c=5  ", a, b, c);
;    c=a&b; /* and */
;    printf("%s, a=%ld, b=%ld, c=%ld\n","c=a&b", a, b, c);
;    c=a|b; /* or */
;    printf("%s, a=%ld, b=%ld, c=%ld\n","c=a|b", a, b, c);
;    c=a^b; /* xor */
;    printf("%s, a=%ld, b=%ld, c=%ld\n","c=a^b", a, b, c);
;    c=~a;  /* not */
;    printf("%s, a=%ld, b=%ld, c=%d\n","c=~a", a, b, c);
;    return 0;
; }

        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
        mov rdi, fmt        ; address of format string
 mov rsi, .str  ; users string
 mov rdx, [a] ; long int a
 mov rcx, [b] ; long int b
 mov r8, [c]  ; long int c
 mov     rax, 0         ; no xmm used
        call    printf          ; Call C function
%endmacro
 
 section .data    ; preset constants, writable
a: dq 3  ; 64-bit variable a initialized to 3
b: dq 5  ; 64-bit variable b initializes to 4
fmt:    db "%s, a=%ld, b=%ld, c=%ld",10,0 ; format string for printf
 
 section .bss   ; unitialized space
c: resq 1  ; reserve a 64-bit word

 section .text  ; instructions, code segment
 global  main  ; for gcc standard linking
main:    ; label
 push rbp  ; set up stack
 
lit5:    ; c=5;
 mov rax,15   ; 5 is a literal constant
 mov [c],rax  ; store into c
 pabc "c=5  "  ; invoke the print macro
 
andb:    ; c=a&b;
 mov rax,[a]   ; load a
 and rax,[b]  ; and with b
 mov [c],rax  ; store into c
 pabc "c=a&b"  ; invoke the print macro
 
orw:    ; c=a-b;
 mov rax,[a]   ; load a
 or rax,[b]  ; logical or with b
 mov [c],rax  ; store into c
 pabc "c=a|b"  ; invoke the print macro
 
xorw:    ; c=a^b;
 mov rax,[a]   ; load a
 xor rax,[b]  ; exclusive or with b
 mov [c],rax  ; store result in c
 pabc "c=a^b"  ; invoke the print macro
 
notw:    ; c=~a;
 mov rax,[a]   ; load c
 not rax   ; not, complement
 mov [c],rax  ; store result into c
 pabc "c=~a "  ; invoke the print macro

 pop rbp  ; restore stack
 mov     rax,0           ; exit code, 0=normal
 ret   ; main returns to operating system

c=5  , a=3, b=5, c=15
c=a&b, a=3, b=5, c=1
c=a|b, a=3, b=5, c=7
c=a^b, a=3, b=5, c=6
c=~a , a=3, b=5, c=-4