https://github.com/nanochess/ti994a
TI994A snippets (Astro Cube and Hello)
https://github.com/nanochess/ti994a
game ti994a
Last synced: 3 months ago
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TI994A snippets (Astro Cube and Hello)
- Host: GitHub
- URL: https://github.com/nanochess/ti994a
- Owner: nanochess
- Created: 2018-03-10T01:42:29.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2018-04-16T17:52:32.000Z (about 7 years ago)
- Last Synced: 2025-01-14T07:53:37.304Z (5 months ago)
- Topics: game, ti994a
- Language: Assembly
- Size: 41 KB
- Stars: 4
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.txt
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README
TI99/4A examples suite.
by Oscar Toledo G. http://nanochess.org/
Here you'll find some samples of code I've wrote for
the TI99/4A.
This computer is based on the TMS9900 processor but has
a TMS9918 video processor and SN76489 sound chip just
like the Colecovision, though the TI99 has only 256
bytes of internal memory.
The cartridges are loaded typically at >6000 thru >7FFF
hello.asm A simple Hello program
astrocube.asm Astro Cube game written for the 4K compo
at Atariage, won 5th place of 9.
http://atariage.com/forums/topic/276364-4k-shortnsweet-game-contest-submissions/
https://www.youtube.com/watch?v=0vg2Msq2pCM
You'll find a short resume of TI99/4A hardware at the
start of each example.
Also I've took note of the default VDP/VRAM configuration
after starting a cartridge, because this saves bytes and
time preparing the system.
I found the TMS9900 16-bits processor not so different of
Intellivision CP1610 processor.
The TMS9900 has 16 registers named R0-R15, you need to
setup a workspace because registers are preserved in RAM,
called scratchspace because is a very high-speed memory.
The stack pointer is recommended in R10, the Link Pointer
is in R11 (Branch & Link instruction)
The memory is addressed in bytes.
My main reference for assembler programming was this one:
http://www.unige.ch/medecine/nouspikel/ti99/assembly.htm
Comments are started by an asterisk, these should be
separated by at least two spaces from mnemonics or operands.
Hexadecimal numbers are preceded with >
Labels must carry a @ symbol to distinguish them from
registers, except in immediate instructions like LI, AI
and CI.
Same as Intellivision and 6502, substraction carry sense
is reversed. (Carry set equals no carry)