0xrsydn/gameboy-rust
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feat(memory): sample Thumb IWRAM refill targets

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After successful refill instructions, sample the Thumb IWRAM target and target+2 halfwords to establish bus history. Share ARM/Thumb refill classification with nominal timing. Respect restored instruction state, completed data accesses, region limits, and diagnostic rollback; keep instruction execution and nominal costs unchanged.

Add original regressions for ARM/Thumb BX, Thumb branches and BL, PC writes, stack/block PC loads, status-restoring returns, real SWI/IRQ returns, both target alignments, mirrors/wrap, captured sample ordering, load lanes, failure retention, BIOS isolation, and DMA invalidation. Document official ARM7TDMI refill evidence and the distinction from a full pipeline.

Darwin arm64 validation: 917 workspace tests and 848 core/demo tests per debug/release profile; 39 preparation tests; native ROM windows in both profiles; ten graphics/window smoke modes; fmt, clippy, and rustdoc. Public ARM, Thumb, memory, and BIOS reports remain identical to prior passing results and between profiles. Cold startup, ARM-target refill history, and DMA-to-CPU ordering remain incomplete; no hardware-conformance or commercial-game claim.
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0xrsydn 2026-10-06 02:04:07 +07:00
commit 8b0f1a5ead
12 changed files with 566 additions and 35 deletions
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9
crates/gba-core/src/cpu/timing.rs
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@ -1,5 +1,5 @@
//! Nominal ARM7 instruction-cycle summaries, separate from instruction semantics.
//! Data costs come from actual bus accesses. No speculative pipeline reads occur.
//! Data costs come from actual bus accesses. Bus-history samples are separate from timing calculations.
//! PC writes use target-region code costs, following GBATEK's cycle summary.
use super::{Cpu, CpuError, InstructionSet};
@ -151,8 +151,11 @@ impl Cpu {
// Share the existing control-flow classification with bounded bus history.
// A PC write can refill even when its target equals the sequential address.
pub(super) fn thumb_refills(&self, instruction: u32) -> bool {
self.thumb_summary(instruction).refill
pub(super) fn instruction_refills(&self, instruction: u32) -> bool {
match self.instruction_set {
InstructionSet::Arm => self.arm_summary(instruction).refill,
InstructionSet::Thumb => self.thumb_summary(instruction).refill,
}
}
fn thumb_summary(&self, instruction: u32) -> Summary {