asm

; -----------------------------------------------------------------------------
; A 64-bit command line application to compute x^y.
;
; Syntax: power x y
; x and y are (32-bit) integers
; -----------------------------------------------------------------------------
 
        global  main
        extern  printf
        extern  puts
        extern  atoi
 
        section .text
main:
        push    r12                     ; save callee-save registers
        push    r13
        push    r14
        ; By pushing 3 registers our stack is already aligned for calls
 
        cmp     rdi, 3                  ; must have exactly two arguments
        jne     error1
 
        mov     r12, rsi                ; argv
 
; We will use ecx to count down form the exponent to zero, esi to hold the
; value of the base, and eax to hold the running product.
 
        mov     rdi, [r12+16]           ; argv[2]
        call    atoi                    ; y in eax
        cmp     eax, 0                  ; disallow negative exponents
        jl      error2
        mov     r13d, eax               ; y in r13d
 
        mov     rdi, [r12+8]            ; argv
        call    atoi                    ; x in eax
        mov     r14d, eax               ; x in r14d
 
        mov     eax, 1                  ; start with answer = 1
check:
        test    r13d, r13d              ; we're counting y downto 0
        jz      gotit                   ; done
        imul    eax, r14d               ; multiply in another x
        dec     r13d
        jmp     check
gotit:                                  ; print report on success
        mov     rdi, answer
        movsxd  rsi, eax
        xor     rax, rax
        call    printf
        jmp     done
error1:                                 ; print error message
        mov     edi, badArgumentCount
        call    puts
        jmp     done
error2:                                 ; print error message
        mov     edi, negativeExponent
        call    puts
done:                                   ; restore saved registers
        pop     r14
        pop     r13
        pop     r12
        ret
 
answer:
        db      "%d", 10, 0
badArgumentCount:
        db      "Requires exactly two arguments", 10, 0
negativeExponent:
        db      "The exponent may not be negative", 10, 0

;(function()
{
  // CommonJS
  SyntaxHighlighter = SyntaxHighlighter || (typeof require !== 'undefined'? require('shCore').SyntaxHighlighter : null);

  function Brush()
  {
    // Contributed by William Jojo
    // https://programmingby.design
    var datatypes =	'RESB RESW RESD RESQ REST RESO RESDQ RESY RESZ '
            + 'DB DW DD DQ DT DO DY DZ DDQ '
            + 'byte word dword qword tword oword yword zword ptr'
            ;

    var keywords = 'bits default section segment absolute extern global common static '
            + 'equ times prefix gprefix lprefix postfix gpostfix lpostfix cpu float'
            ;

    this.regexList = [

      { regex: SyntaxHighlighter.regexLib.singleQuotedString,		css: 'string' },
      { regex: SyntaxHighlighter.regexLib.doubleQuotedString,		css: 'string' },
      { regex: /%?[re]?(ax|bx|cx|dx|sp|bp)/gi, css: 'color1' },	// registers
      { regex: /%?([csdefg]s|[abcd][lh]|(si|di)[hl])/gi, css: 'color1' },	// registers
      { regex: /%?((frp|mmx)[0-7]|xmm1[0-5]|xmm[0-9])/gi, css: 'color1' },	// registers
      { regex: /\$?(-?\.?)(\b(\d*\.?\d+|\d+\.?\d*)(e[+-]?\d+)?|0x[a-f\d]+)\b\.?/gi, css: 'color2' },	// numbers
      { regex: new RegExp(this.getKeywords(datatypes), 'gmi'),		css: 'variable' },	// datatypes
      { regex: new RegExp(this.getKeywords(keywords), 'gmi'),		css: 'keyword' },
      { regex: /;.*$/,	css: 'comments' },
      { regex: /^(\.|\.\.@)?[a-zA-Z0-9]+:?/,	css: 'comments' }
    ];
    this.forHtmlScript(SyntaxHighlighter.regexLib.aspScriptTags);
  };

  Brush.prototype	= new SyntaxHighlighter.Highlighter();
  Brush.aliases	= ['asm'];

  SyntaxHighlighter.brushes.Asm = Brush;

  // CommonJS
  typeof(exports) != 'undefined' ? exports.Brush = Brush : null;
})();