Removed an unecessary conditional jump in main.asm, saving 7 cycles and 2 bytes. Removed a function called "subDEfromHL" or something like that, and replaced it with `sbc hl, de`, saving 10 bytes total and 61 cycles. I also rewrote enterParens and strlen to use cpir instead of cpi in a loop, saving 14 cycles per character and also 6 bytes (bc needed to be zeroed in enterParens).
I replaced some doubled up nops with pushes and pops again, saving two bytes. There was also a nop in a loop that didn't look necessary, since the jump back to the top of the loop is already 13 cycles, so way more than 80 cycles are spent in that loop anyway.
I reworked things a little in parseHexPair and saved 5 bytes and 6 cycles, with more cycles saved in error cases.
There were some doubled up nop's, so I replaced them with paired pushes and pops, saving 4 bytes and wasting 2-3 extra cycles over the original nop's, so there shouldn't be a problem with not waiting long enough.
* Fix for tools/zasm.sh being dependent on readlink -f (an issue on macOS, preventing builds)
* Wrap zasm.sh shebang in /usr/bin/env ; remove comment about BSDs
* Optimised intoXX functions
Rewrote intoXX functions to mainly rely on intoHL, as the HL instructions are smaller and faster. Also removed some redundant push and pop instructions. I edited the given unit tests to test these, and they seem to work as expected.
* Doesn't use self-modifying code
The number of bytes is the same as my previous attempt, with 11 more cycles in intoHL, so although I don't feel as clever this time it's still a good optimisation. I found an equivalent method for intoDE, however relying on intoHL still allows for `ex (sp), hl` to be used in intoIX, which is smaller and faster.
* Update core.asm
* Tried harder to follow coding convention
Added tabs between mnemonics and operands, and replaced a new line I accidentally removed.
I've tested RAM usage when self-assembling and there weren't as high
as I thought. zasm's defaults now use less than 0x1800 bytes of RAM,
making it possible, theoretically for now, for a Sega Master System
to assemble Collapse OS from within itself.
Yup, that's ultimately why I've just made this whole big zasm
refactoring in the previous commits. To allow for this.
But also, zasm is in much better shape now...
I'm about to split the global registry in two (labels and consts)
and the previous state of registry selection made things murky.
Now it's much better.
