Program Challenge (was Re: z80 timing... 6502 timing)

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Mon Apr 19 16:18:34 1999

> > MOV CL, 4
> > SHL AX, 4
> > RET

> Why not SHL AX,4?


Because the 8088 didn't HAVE a shift immediate instruction. Check with
Allison about which processor introduced it, and when it cam out. Was 286
<= 1983?

OOOPs! the code should be replaced by:

;entry condition:
; AX contains number
; DS contains location of data segment
; content of data segment same as before
;exit condition:
; DS:0 points to result
;code:
        ADD DS, AX
        RET
--
Fred Cisin                      cisin_at_xenosoft.com
XenoSoft                        http://www.xenosoft.com
2210 Sixth St.                  (510) 644-9366
Berkeley, CA 94710-2219
Received on Mon Apr 19 1999 - 16:18:34 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:31:44 BST