17.05.2015 Views

TI486 Microprocessor - Al Kossow's Bitsavers

TI486 Microprocessor - Al Kossow's Bitsavers

TI486 Microprocessor - Al Kossow's Bitsavers

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

General Instruction Format<br />

7.1 General Instruction Format<br />

Figure 7-1. General Instruction Format<br />

<strong>Al</strong>l of the <strong>TI486</strong>SLC/DLC machine instructions follow the general instruction<br />

format shown in Figure 7-1. These instructions vary in length and can start at<br />

any byte address. An instruction consists of one or more bytes that can<br />

include: prefix byte(s), at least one opcode by te(s) , mod rIm byte, s-i-b byte,<br />

address displacement byte(s) and immediate data byte(s). An instruction can<br />

be as short as one byte and as long as 15 bytes. If there are more than 15 bytes<br />

in the instruction, a general protection fault (error code of 0) is generated.<br />

I p p p p p p p PiT T T T T T TTl mod R R R rim I ss index base I d321161al none id321161al none<br />

7 07 0765320765320<br />

optional prefix<br />

byte(s)<br />

opcode<br />

(one or two bytes)<br />

mod rim<br />

byte<br />

s-i-b<br />

byte<br />

address<br />

displacement<br />

/<br />

(4, 2, 1 bytes,<br />

or none<br />

\1...-___----. ,---___---'. )<br />

V<br />

register and address<br />

mode specifier<br />

immediate<br />

data<br />

(4,2, 1 bytes,<br />

or none)<br />

P - prefix bit<br />

T - opcode bit<br />

R - opcode bit or reg bit<br />

7-4<br />

Instruction Set

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!