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PSIM
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Author
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Peter Bui <pbui@cse.nd.edu>
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Description
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PSIM is simple assembler/simulator suite for the ISA found in Vahid's Digital
Design textbook. The syntax of the assembler mostly follows that of the
textbook with the exception that semi-colons are not needed at the end of each
assembly line. Likewise, the code is split into a data and text segment
resembling that of MIPS. This is because the simulator uses a unified memory
architecture. Example assembly source code is available in this package.
The software is still requires testing and bug checking, so please free feel to
file bug reports or suggestions.
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ChangeLog
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* 11/07/2007
- Assembler supports MOVR R1, R0, @A (ie. label constant for MOVR)
- Assembler supports WORD 0, 1, 2, 3, 4 (ie. comma separated array)
* 11/06/2007
- Changed pasm to output either unified memory or non-unified memory
binary file (psim requires unified memory, default is non-unified
memory that works with verilog)
* 11/01/2007
- Support files made on Windows (ie. \r\n end of lines)
- Assembler outputs error when label is undefined
* 10/18/2007
- Implemented MOV I/O assembler and simulator instruction
* 10/16/2007
- Implemented MOVR
- Added Address-field type to assembler so that you can load actual
addresses:
MOV R0, @A // Converts address of label A to constant
- Changed assembler to use token_is_* helper functions (this fixes the
JMP label bug)
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Known Bugs/Issues
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* 10/11/2007: JMP, JMPN, JMPZ only work w/ labels and not numeric offsets
10/16/2007: Fixed in latest version
* 10/11/2007: Labels must be on the same line as instruction:
Foo:
MOV R0, #1 // Invalid
Foo: MOV R0, #1 // Valid
* 10/16/2007: Non-existant labels do not throw error in assembler
11/01/2007: Fixed in latest version
* 10/16/2007: pasm doesn't handle multiple files correctly
10/17/2007: Fixed in latest version
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Build
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Extract the tarball and run make:
$ tar -xzvf psim.tar.gz
$ cd psim
$ make
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Usage
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To use the assembler:
$ ./pasm ex1.s
This will create a non-unified memory binary output file ex1.bin
$ ./pasm u ex1.s
This will create a unified memory binary output file ex1.ubin
To use the simulator:
Command Description
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l <file> Load binary file (must be unified memory)
i <p> <v> Set pregister <p> to <v>
o Print i/o pregister file
p Print register file, i/o, and memory
m <s> <e> Print memory regions from s to e (s defaults to 0, e to end of memory)
r Print register file
s <n> Step n times (n defaults to 1)
q Quit this program
$ ./psim
[0000]-> l ex1.ubin
[0001]-> p
[0002]-> i 2 50
[0003]-> s 100
[0004]-> r
[0005]-> q
This loads the source binary, prints out the register, io, and memory contents,
sets io p-register 2 to 50, steps 100 times, prints out the register contents
and then quits. Check out the help message by entering 'h' into psim to find
out about the other commands in the simulator.
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