Using the Assembler

In order to test your project, you need to assemble programs to be loaded into memory. To do this, there is a simple assembler provided. It will take source code that looks like the text in figure below and produces two files: An object file and a listing for your reference.

slbi	r1, 0
slbi	r1, 0x55
slli	r2, r1, 8
bnez	r2, .LAB3
subi    r2, r2, 1
.LAB3:
halt

@0
9100
9155
a948
6a01
4a41
0000

0000 9100 slbi	r1, 0
0001 9155 slbi	r1, 0x55
0002 a948 slli	r2, r1, 8
0003 6a01 bnez	r2, .LAB3
0004 4a41 subi    r2, r2, 1
0005      .LAB3:
0005 0000 halt

The assembler is located here: /u/k/a/karu/courses/cs552/spring2013/handouts/bins/assemble.sh

That directory has already been added to your PATH variable.

Say you have a source file names "myfile.asm"; to assemble it, type: assemble.sh myfile.asm

This produces many files, two of the files are: The listing file is called loadfile.lst and the object file is the second name specified (loadfile_all.img).

The assembler always produces a warning that if there are any errors, the output is not valid. This is just a reminder -- this message itself is not an error.

See running the programs in the WISC-SP13 simulator-debugger.

The assembler will also produce 4 files of the form loadfile_0,1,2,3.img. These are binary images you can load into the four-banked memory when you get to it. You load one of these files into each bank.

Assembler Syntax

Assembly programs are written using the semantics outlined in the WISC-SP13 ISA document. C style comments can be used (//). Static data and labels can be used as follows:

Labels:

beqz r0, .label1

.label1:
<-- code here -->

Static data:

lbi r0, L.DataArea //load the lower half of datum
slbi r0, U.DataArea //load the upper half of datum

.DataArea
data 0x1234
data 0x5678