Subject: Re: [stella] Light gun/pen From: Nick S Bensema <nickb@xxxxxxxxxxxx> Date: Tue, 30 Sep 1997 12:36:44 -0700 (MST) |
>ObProgramming: How long do you think it would take someone who has >only had one 8086 assembly language course about five years ago to >catch on to the 6507? I guess it depends, how well did you do in the 8086 class? Looks like you've got a head-start, knowing about dealing with individual bits and bytes. You just need to find a good reference, though a tutorial would probably be better. Whenever I try to learn from scratch with a reference, I can't pace myself, and always try to read too much and never absorb anything. But considering there aren't many opcodes or addressing modes, I'd say you could learn the whole thing in a month. Though it'll take you a while to learn the techniques and nuances, like the overflow bit and exactly what gets pushed to the stack when you JSR. Here's a six-line head-start on the mnemonics, though....enough to give you a teeny bit of literacy when reading source code. Remember in branching instructions and stuff, that the P register keeps certain details about the last mathemetical or read operation. Operands: #$constant $address $address-plus-x,x ($pointer) LDx Load register x ADC: A+= Cycle in carry: Branch if: STx Store contents of register x. SBC: A-= YES NO result=0 BEQ !=0 BNE JMP,JSR,RTS == GOTO, GOSUB, RETURN INX: X++ ROL << ASL carry=1 BCS =0 BCC PH?, PL? == push, pop A or P DEY: Y-- ROR >> LSR result>0 BPL < BMI T?? Transfer registers, AX etc AND, ORA, XOR: Boolean SEC C=0 CLC C=1 Meaningless enough for you? I don't know why I just typed it... but I guess I can't do all that hard work without sending it to the list. -- Archives updated once/day at http://www.biglist.com/lists/stella/archives/ Unsubscribing and other info at http://www.biglist.com/lists/stella/stella.html
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