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Re: ROM adventures (dev7rom)
Posted: 26 Feb 2025, 01:42
by lb3361
Correct. I have fixed the doc.
Note that, as of today, EXBA is only used in the microkernel of the multithreading example
https://github.com/lb3361/gigatron-lcc/ ... ff/threads
The callable functions are in threads.h and the kernel in threads.s.
Re: ROM adventures (dev7rom)
Posted: 27 Feb 2025, 18:58
by Phibrizzo
Can You check MOVW (opcode $BC) instruction?
Propably it working bad. I chceked on latest dev7.rom of ROM file.
Re: ROM adventures (dev7rom)
Posted: 27 Feb 2025, 21:23
by lb3361
Documentation error again
. The opcode is $bb.
In general, the opcode information in interface-dev.json is the most reliable because this is the source of truth for the c compiler and because the rom compilation process checks that it matches the labels in the rom source. That said, I am happy to fix these embarrassing documentation errors.
MOVW is an instructions that seems very simple but is hard to implement on the gigatron. I am not happy that it takes 36 cycles. On the other hand, it saves one byte relative to LDW+STW and sometimes even more because vAC is preserved.