📄 http:^^cs.nyu.edu^cs^dept_info^course_home_pages^fall96^v22.0201.002^shiftadd.html
字号:
Date: Tue, 14 Jan 1997 22:48:32 GMTServer: NCSA/1.4.1Content-type: text/htmlLast-modified: Mon, 21 Oct 1996 00:18:13 GMTContent-length: 915<HTML><HEAD> <META NAME="GENERATOR" CONTENT="Adobe PageMill 2.0 Mac"> <TITLE>shift and add = multiply</TITLE></HEAD><BODY BGCOLOR="#fee7cb"><PRE>; code to demonstrate the shift & add method of multiplication;;; presume the input is in two bytes named fact1 and fact2; and the output is going into a Word (unsigned) called PRODUCT;; mov bl, fact1 ; grab input mov al, fact2 mov bh, 0 ;zero out high byte of bx mov dx, 0 ;zero accum (product)lp: cmp al, 0 ;check for end je fini shr al, 1 ;grab rightmost bit jnc nextbit ;don't add it -bit was zero add dx, bx ;add next shift into accumnextbit: shl bx, 1 ;shift first fact to left jmp lpfini: mov product, dx </PRE></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -