Computer Architecture Lab/WS2008/Group2/Documentation

Members of Group 2, Sweet16

• Franz-Josef Katzdobler, 0425195
• Daniel Reichhard, 0025792
• Stefan Resch, 0425306
• Matthias Wenzl, 0425388

Instruction Set

Assembler

The man page:

S16ASM(1)                        User Manuals                        S16ASM(1)

NAME
       s16asm - sweet 16 assembler

SYNOPSIS
       s16asm [-b | h | l | d | r] [-n][-o outfile ] [ infile ...]

DESCRIPTION
      s16asm Transforms the given assembler source files to the selected des-
      tination format in the given order. If no infile is given,  stdin  will
      be used. The default destination format is raw.

OPTIONS
      -b     Output bytes in ASCII as binary number.

      -h     Output bytes in ASCII as hex number in format of hexdump.

      -l     Output as listing.

      -r     Output as vhdl rom description.

      -d     Output in format for bootloader.

      -n     Supress warnings.

      -o outfile
             Place output to file outfile. Otherwise use stdout.

BUGS
      Currently none know. Please send a mail when you find one.
 
AUTHOR
       Stefan Resch Matthias Wenzl Daniel Reichhard Franz Katzdobler

Sweet16                          NOVEMBER 2008                       S16ASM(1)

Assembler program for illustration:

//
//  Short example for s16asm Assembler
//
//  incrementing one number until it reaches 0xFCCF
//  and enter endless loop afterwards
//

.org 0                  // default orgin of first command is 0 anyway
.equ number r5
.equ start 64
.equ dest 0xFCCF

.org 0x0100

	movi number, start
	movi r6, >dest      // Low Byte
	movih r6, <dest     // High Byte
.redo:
//	calli memfun
	mov r11, number     // r11 ... first parameter register
	calli increment
	mov number, r0      // r0  ... first return register
	sub r0, r6
	brsnz redo          // numbers not equal
	
.endless:
	nop                 // nop is not necessary
	jmpi endless        // endless loop

//.org 20		// notice org directives must be higher than the previously
		// written instruction

function increment (number1): // parameter number1 ... r11
	mov out, number1
	movi number1, >-1
	movih number1, <-1   // don't forget the sign extension
	sub out, number1      // use names for readability
	ret
end function (out)            // return register ... r0

function memfun:
	push r5
	pop r1
	movi r1, 0
	ld r2, r1
	movi r2, 19
	st r2, r5
	ret
end function

Pipelining

The pipeline itself consists of 4 Stages:

• Fetch
• Decode
• Execute
• Memory Stage

You can see the functional description [here].

The interaction with the buttons, leds and all kinds of memories is managed by a memory interface unit. Following memory mapping is applied: