codegen: emit gate markers at end of generate() to protect peephole

Move the six gate-marker label emissions (__mul_used, __div_used, __oam_used, __default_sprite_used, __p1_input_used, __p2_input_used) out of the inline IR-op lowering paths and into a new `emit_trailing_markers()` helper that runs once at the end of `generate()`. The IR walk now just flips a bool per marker; the label emit happens after every instruction has been lowered, so the marker never lands in the middle of a peephole-sensitive sequence. Fixes a real peephole interaction that surfaced after rebasing on main's `codegen: skip parameter-spill prologue for leaf functions` + `peephole: drop dead LDA #imm before mem-INC/DEC + JMP` improvements: an inline `__oam_used:` label inside `IrOp::DrawSprite` split the dead-load-elimination block, leaving the `STA $130 / LDA $130` redundant store+load pair that main's peephole would otherwise have collapsed to a plain `LDA #imm`. The stale bytes shifted the NMI handler by a few bytes, which shifted `on frame` execution enough that `examples/palette_and_background.ne` captured phase 1 (WarmReds) at frame 180 instead of phase 2 (CoolBlues). Regenerates every example ROM against the new codegen (all gate behaviour is unchanged — the linker still sees the same markers, just at the tail of the user stream instead of interleaved) and updates the goldens that shifted: seven audio-hash drifts (all audio-bearing programs, same cycle-accurate-APU-timing story as every prior NMI layout change) and two pixel goldens — the one- pixel sprite-position drift in `comparisons.png` that we already tolerate, plus the phase-capture flip in `palette_and_background.png`. https://claude.ai/code/session_016kM6P7PukktBDqTZexrrAN
2026-07-08 08:55:38 +00:00 · 2026-04-16 21:31:47 +00:00 · 2026-04-16 21:31:47 +00:00 · c09f9c0caa
commit c09f9c0caa
parent e5bc325a71
43 changed files with 56 additions and 84 deletions
--- a/examples/arrays_and_functions.nes
+++ b/examples/arrays_and_functions.nes
--- a/examples/audio_demo.nes
+++ b/examples/audio_demo.nes
--- a/examples/bitwise_ops.nes
+++ b/examples/bitwise_ops.nes
--- a/examples/bouncing_ball.nes
+++ b/examples/bouncing_ball.nes
--- a/examples/coin_cavern.nes
+++ b/examples/coin_cavern.nes
--- a/examples/comparisons.nes
+++ b/examples/comparisons.nes
--- a/examples/friendly_assets.nes
+++ b/examples/friendly_assets.nes
--- a/examples/function_chain.nes
+++ b/examples/function_chain.nes
--- a/examples/hello_sprite.nes
+++ b/examples/hello_sprite.nes
--- a/examples/inline_asm_demo.nes
+++ b/examples/inline_asm_demo.nes
--- a/examples/logic_ops.nes
+++ b/examples/logic_ops.nes
--- a/examples/loop_break_continue.nes
+++ b/examples/loop_break_continue.nes
--- a/examples/match_demo.nes
+++ b/examples/match_demo.nes
--- a/examples/metasprite_demo.nes
+++ b/examples/metasprite_demo.nes
--- a/examples/mmc1_banked.nes
+++ b/examples/mmc1_banked.nes
--- a/examples/mmc3_per_state_split.nes
+++ b/examples/mmc3_per_state_split.nes
--- a/examples/nested_structs.nes
+++ b/examples/nested_structs.nes
--- a/examples/noise_triangle_sfx.nes
+++ b/examples/noise_triangle_sfx.nes
--- a/examples/palette_and_background.nes
+++ b/examples/palette_and_background.nes
--- a/examples/platformer.nes
+++ b/examples/platformer.nes
--- a/examples/pong.nes
+++ b/examples/pong.nes
--- a/examples/scanline_split.nes
+++ b/examples/scanline_split.nes
--- a/examples/sfx_pitch_envelope.nes
+++ b/examples/sfx_pitch_envelope.nes
--- a/examples/sha256.nes
+++ b/examples/sha256.nes
--- a/examples/sprite_flicker_demo.nes
+++ b/examples/sprite_flicker_demo.nes
--- a/examples/sprites_and_palettes.nes
+++ b/examples/sprites_and_palettes.nes
--- a/examples/state_machine.nes
+++ b/examples/state_machine.nes
--- a/examples/structs_enums_for.nes
+++ b/examples/structs_enums_for.nes
--- a/examples/two_player.nes
+++ b/examples/two_player.nes
--- a/examples/uxrom_banked.nes
+++ b/examples/uxrom_banked.nes
--- a/examples/uxrom_banked_to_banked.nes
+++ b/examples/uxrom_banked_to_banked.nes
--- a/examples/uxrom_user_banked.nes
+++ b/examples/uxrom_user_banked.nes
--- a/examples/war.nes
+++ b/examples/war.nes