53 lines
2.4 KiB
Markdown
53 lines
2.4 KiB
Markdown
# COMMON
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Advances some ideas using Steve Wozniak’s 6502 SWEET16 interpreted byte-code language as inspiration. While the goal of SWEET16 was brevity, the goal of COMMON is functionality. The intent is to make a platform suitable for many commercial, scientific, and engineering applications.
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For example:
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* native type is equivalent to fixed-point decimal ±######.###
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* easier support for banked memory
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* easier support for higher language compilers
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* arithmetic operations add, subtract, multiply, divide, and modulus
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* inherent overflow/underflow detection
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* all control branching is 16-bit relative, for easier relocatable code
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* support for custom system/user functions, akin to INT in x86
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Why 6502 and not, for example, x86?
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* 6502 assembler is very easy and has a large archive of existing functions
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* existing 6502 SWEET16 already has the “hard work” done
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* interesting to see it run in newer faster versions of 6502 processors
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* how do you think [Bender](https://spectrum.ieee.org/the-truth-about-benders-brain) does what he does? (or the [Terminator](https://www.apl2bits.net/2016/07/18/terminator-6502/)!)
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Completed:
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* added all the instructions (see `common/common.h` for the list)
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In progress:
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* larger stack size, current stack size is only about 60 numbers, 250 or so would be better
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* emulation of serial ports to allow standard I/O
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* a unit test suite to ensure each instruction is correct
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* a proof-of-concept application with decoupled system and application files
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The meat of the project:
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* `common/common.h`: details of instructions
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* `common/common.asm`: assembler code for the instructions
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* `common/macros.h`: macros used to define the interpreted byte-code
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* `common/appl.src`: sample source file using the macros
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Auxiliary:
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* `emulator/*`: 6502 emulator (borrowed Mike Chambers’ Fake6502 CPU emulator v1.1 ©2011)
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* `xa-pre-process/*`: my utility `xapp` to convert 32-bit fixed decimal quantities so that `xa` can use them
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Right now, for testing purposes, the code builds everything into one file `system.obj` and runs the code in the last block loaded, in this case, the code corresponding to `appl.src`. Eventually will support decoupling of system and application files. Application files will be inherently relocatable.
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To build and run:
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make all
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make run
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The makefiles use `re2c`, `flex`, `bison`, `gcc`, `cpp`, `xa`, `grep`, and `sed`. Will eventually provide a `./configure`.
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