这是书上的一个C写的随机显示矩形的例子,里面调用了C库函数rand().例子显示的飞快.
我用汇编改写了一下.变得很慢,如果把随机数函数改成C库函数rand(),就会变快,看来是随机数函数的问题,但是我的随机数函数很简单啊,为什么会慢呢?
.386
.model flat,stdcall
option casemap:none
include windows.inc
include kernel32.inc
includelib kernel32.lib
include user32.inc
includelib user32.lib
include gdi32.inc
includelib gdi32.lib
include c_stdlib.inc
includelib c_msvcrt.lib
WinMain proto :dword,:dword,:dword,:dword
DrawRectangle proto :dword
myRand proto :dword,:dword
RGB macro red,green,blue
mov ah,blue
shl eax,8
mov ah,green
mov al,red
endm
.data
szAppName db 'randrect',0
.data?
hInstance dd ?
hWinMain dd ?
cxClient dd ?
cyClient dd ?
.code
start:
invoke GetModuleHandle,NULL
mov hInstance,eax
invoke WinMain,hInstance,NULL,NULL,NULL
invoke ExitProcess,NULL
WinMain proc uses edi esi ebx,hInst:HINSTANCE,hPrevInst:HINSTANCE,CmdLine:dword,CmdShow:dword
local wc:WNDCLASSEX
local msg:MSG
mov wc.cbSize,sizeof wc
mov wc.lpfnWndProc,offset WndProc
mov wc.lpszClassName,offset szAppName
mov wc.lpszMenuName,NULL
mov eax,hInstance
mov wc.hInstance,eax
mov wc.style,CS_VREDRAW or CS_HREDRAW
mov wc.cbWndExtra,NULL
mov wc.cbClsExtra,NULL
invoke LoadIcon,NULL,IDI_APPLICATION
mov wc.hIcon,eax
mov wc.hIconSm,eax
invoke LoadCursor,NULL,IDC_ARROW
mov wc.hCursor,eax
invoke GetStockObject,WHITE_BRUSH
mov wc.hbrBackground,eax
invoke RegisterClassEx,addr wc
invoke CreateWindowEx,NULL,offset szAppName,NULL,WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,\
CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL
mov hWinMain,eax
invoke ShowWindow,hWinMain,SW_SHOWNORMAL
invoke UpdateWindow,hWinMain
.while TRUE
invoke PeekMessage,addr msg,NULL,0,0,PM_REMOVE
.if eax
.break .if (msg.message==WM_QUIT)
invoke TranslateMessage,addr msg
invoke DispatchMessage,addr msg
.else
invoke DrawRectangle,hWinMain
.endif
.endw
mov eax,msg.wParam
ret
WinMain endp
WndProc proc uses edi esi ebx,hWnd:HWND,uMsg:UINT,wParam:WPARAM,lParam:LPARAM
.if uMsg==WM_DESTROY
invoke PostQuitMessage,NULL
.elseif uMsg==WM_SIZE
mov eax,lParam
shr eax,16
mov cyClient,eax
mov eax,lParam
and eax,0ffffh
mov cxClient,eax
.else
invoke DefWindowProc,hWnd,uMsg,wParam,lParam
ret
.endif
xor eax,eax
ret
WndProc endp
DrawRectangle proc uses ebx edi esi,hWnd:HWND
local hdc:HDC
local hBrush
local rect:RECT
local tmp1
local tmp2
local tmp3
local tmp4
local tmp5:byte
local tmp6:byte
local tmp7:byte
.if (cxClient==0||cyClient==0)
ret
.endif
;COMMENT!
invoke myRand,0,cxClient
mov tmp1,eax
invoke myRand,0,cyClient
mov tmp2,eax
invoke myRand,0,cxClient
mov tmp3,eax
invoke myRand,0,cyClient
mov tmp4,eax
;!
COMMENT!
;rand()%cxClient,rand()%cyClient
;使用C库函数rand()取得随机数
invoke rand
xor edx,edx
div cxClient
mov tmp1,edx
invoke rand
xor edx,edx
div cyClient
mov tmp2,edx
invoke rand
xor edx,edx
div cxClient
mov tmp3,edx
invoke rand
xor edx,edx
div cyClient
mov tmp4,edx
!
invoke SetRect,addr rect,tmp1,tmp2,tmp3,tmp4
COMMENT!
invoke myRand,0,256
mov tmp5,al
invoke myRand,0,256
mov tmp6,al
invoke myRand,0,256
mov tmp7,al
!
;COMMENT!
;使用C库函数rand()取得随机数
mov ebx,256
invoke rand
xor edx,edx
div ebx
mov tmp5,dl
invoke rand
xor edx,edx
div ebx
mov tmp6,dl
invoke rand
xor edx,edx
div ebx
mov tmp7,dl
;!
RGB tmp5,tmp6,tmp7
invoke CreateSolidBrush,eax
mov hBrush,eax
invoke GetDC,hWnd
mov hdc,eax
invoke FillRect,hdc,addr rect,hBrush
invoke ReleaseDC,hWnd,hdc
invoke DeleteObject,hBrush
ret
DrawRectangle endp
myRand proc uses ebx min:dword,max:dword
mov ebx,max
sub ebx,min
invoke GetTickCount
xor edx,edx
div ebx
add edx,min
mov eax,edx
ret
myRand endp
end start
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