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recompiler: fold PSX main RAM dispatch mirrors

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(cherry picked from commit d0f3e950a9c0ddc080db7c8b74d7b24fba73435d)
This commit is contained in:
Alexandros Mandravillis
2026-08-23 19:43:23 +03:00
parent 01c647e8a2
commit 2c52b467c6
2 changed files with 16 additions and 0 deletions
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recompiler/src/bios_address_model.cpp
+8
View File
@@ -105,6 +105,12 @@ BiosAddressModel BiosAddressModel::from_config(const BiosConfig& cfg) {
uint32_t BiosAddressModel::normalize(uint32_t addr) const {
uint32_t phys = addr & 0x1FFFFFFFu;
// The 2 MiB main RAM is mirrored four times across the first 8 MiB of
// physical address space. Dispatch keys must use the same hardware alias
// as ordinary memory reads, or a valid call through 0x80200000+
// incorrectly becomes an unmapped-PC failure.
if (phys < 0x00800000u)
phys &= 0x001FFFFFu;
// Sequential per-copy folds, same shape as the emitted normalize() —
// equivalence to first-match-wins is enforced by from_config.
for (const BiosAddrCopy& c : copies_) {
@@ -217,6 +223,8 @@ std::string BiosAddressModel::emit_normalize_c() const {
std::string out;
out += "static uint32_t normalize(uint32_t addr) {\n";
out += " uint32_t phys = addr & 0x1FFFFFFFu;\n";
out += " /* PSX main RAM: 2 MiB mirrored through physical 0x007FFFFF. */\n";
out += " if (phys < 0x00800000u) phys &= 0x001FFFFFu;\n";
for (const BiosAddrCopy& c : copies_) {
if (c.key_is_ram) {
out += fmt::format(" /* {}: ROM 0x{:X}+ -> RAM 0x{:X}+ */\n",
recompiler/tests/bios_address_model_test.cpp
+8
View File
@@ -160,6 +160,14 @@ int main(int argc, char** argv) {
sweep(0xBFC00000u, 0xBFC80000u); // BIOS ROM KSEG1 (mask path)
sweep(0x80000000u, 0x80200000u); // RAM KSEG0 (mask path)
// Main RAM aliases cover the first 8 MiB of physical space. Dispatch
// normalization must agree with memory access normalization at every
// mirror, including the exact 0x80200000 boundary seen in indirect calls.
expect_eq(model.normalize(0x00200000u), 0x00000000u, "normalize.ram_mirror", 0x00200000u);
expect_eq(model.normalize(0x007FFFFCu), 0x001FFFFCu, "normalize.ram_mirror", 0x007FFFFCu);
expect_eq(model.normalize(0x80200000u), 0x00000000u, "normalize.ram_mirror", 0x80200000u);
expect_eq(model.normalize(0xA07FFFFCu), 0x001FFFFCu, "normalize.ram_mirror", 0xA07FFFFCu);
// --- kbless / rom-keyed accessors match the SCPH1001 constants --------
if (!model.has_kbless()) { std::fprintf(stderr, "FAIL: no kbless window\n"); g_failures++; }
expect_eq(model.kbless_ram_lo(), 0x500u, "kbless_ram_lo", 0);