mirror of
https://github.com/imjasonh/nescript
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db3a4adc57
Programs that put functions in switchable banks can now call across
bank boundaries — `bank A { fun step() { helper() } }` where
`helper` lives in `bank B` used to panic in the IR codegen. Three
small pieces unblock it:
1. **Generic trampoline.** `runtime/gen_bank_trampoline` no longer
takes a `fixed_bank_index` argument. Instead it reads the
caller's current bank from `ZP_BANK_CURRENT`, pushes it on the
hardware stack, switches to the target, JSRs the entry, then
pulls and restores the saved bank. The same per-callee stub
works for fixed→banked and banked→banked direction; nested
trampolines compose because each PHA/PLA pair sits inside its
own JSR/RTS frame. `gen_mapper_init` seeds `ZP_BANK_CURRENT`
with the fixed bank index for any banked mapper so the very
first cross-bank call from the fixed bank still restores to
the fixed bank (matching pre-banked-banked semantics).
2. **Codegen drops the panic.** The `Some(from), Some(to)` arm in
the call-resolution switch now emits `JSR __tramp_<name>` like
the fixed→banked case instead of panicking. Banked→fixed calls
still go direct (the fixed bank is always mapped at $C000).
3. **Bank-namespaced local labels.** Two banks emitting the same
`__ir_cmp_e_8` would trip the linker's discovery-pass duplicate-
label check the moment any banked code generated a comparison.
The new `local_label_suffix` helper prefixes the suffix with the
current bank name when banked code is being emitted, leaving
fixed-bank label generation untouched (so existing examples are
byte-identical apart from the trampoline / init bytes
themselves).
The new `examples/uxrom_banked_to_banked.ne` demonstrates the path
end-to-end: `bank Logic { fun step() { ... clamp() } }` calls
`bank Helpers { fun clamp() { ... } }` once per frame. The harness
golden is committed alongside it. The five existing banked example
ROMs change byte-for-byte because of the new trampoline shape and
the seed-ZP_BANK_CURRENT init, but their emulator goldens still
match exactly — observable behaviour is unchanged.
https://claude.ai/code/session_01KEczoNUX3WmcFLfq6iAQxB
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| .. | ||
| arrays_and_functions.audio.hash | ||
| arrays_and_functions.png | ||
| audio_demo.audio.hash | ||
| audio_demo.png | ||
| bitwise_ops.audio.hash | ||
| bitwise_ops.png | ||
| bouncing_ball.audio.hash | ||
| bouncing_ball.png | ||
| coin_cavern.audio.hash | ||
| coin_cavern.png | ||
| comparisons.audio.hash | ||
| comparisons.png | ||
| friendly_assets.audio.hash | ||
| friendly_assets.png | ||
| function_chain.audio.hash | ||
| function_chain.png | ||
| hello_sprite.audio.hash | ||
| hello_sprite.png | ||
| inline_asm_demo.audio.hash | ||
| inline_asm_demo.png | ||
| logic_ops.audio.hash | ||
| logic_ops.png | ||
| loop_break_continue.audio.hash | ||
| loop_break_continue.png | ||
| match_demo.audio.hash | ||
| match_demo.png | ||
| mmc1_banked.audio.hash | ||
| mmc1_banked.png | ||
| mmc3_per_state_split.audio.hash | ||
| mmc3_per_state_split.png | ||
| nested_structs.audio.hash | ||
| nested_structs.png | ||
| noise_triangle_sfx.audio.hash | ||
| noise_triangle_sfx.png | ||
| palette_and_background.audio.hash | ||
| palette_and_background.png | ||
| platformer.audio.hash | ||
| platformer.png | ||
| scanline_split.audio.hash | ||
| scanline_split.png | ||
| sprites_and_palettes.audio.hash | ||
| sprites_and_palettes.png | ||
| state_machine.audio.hash | ||
| state_machine.png | ||
| structs_enums_for.audio.hash | ||
| structs_enums_for.png | ||
| two_player.audio.hash | ||
| two_player.png | ||
| uxrom_banked.audio.hash | ||
| uxrom_banked.png | ||
| uxrom_banked_to_banked.audio.hash | ||
| uxrom_banked_to_banked.png | ||
| uxrom_user_banked.audio.hash | ||
| uxrom_user_banked.png | ||
