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Refactor physical memory address resolution code

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The physical memory layout is the same whether we use the MMU or not, so
let's implement it only once.
This commit is contained in:
jn 2023-01-28 19:44:44 +01:00
parent ee4b96db4f
commit c739f8ecb3
1 changed files with 27 additions and 40 deletions
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67
src/cpu.c
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@ -420,28 +420,33 @@ static uint32_t *vm_findlocal(vm_t *vm, uint8_t local) {
vm_panic(vm, FOX32_ERR_BADREGISTER);
}
static uint8_t *vm_findmemory(vm_t *vm, uint32_t address, uint32_t size, bool write) {
static uint8_t *vm_findmemory_phys(vm_t *vm, uint32_t address, uint32_t size, bool write) {
uint32_t address_end = address + size;
if (address_end > address) {
if (address_end <= FOX32_MEMORY_RAM) {
return &vm->memory_ram[address];
}
if (
!write &&
(address >= FOX32_MEMORY_ROM_START) &&
(address -= FOX32_MEMORY_ROM_START) + size <= FOX32_MEMORY_ROM
) {
return &vm->memory_rom[address];
}
}
if (!write) {
vm->exception_operand = address;
vm_panic(vm, FOX32_ERR_FAULT_RD);
} else {
vm->exception_operand = address;
vm_panic(vm, FOX32_ERR_FAULT_WR);
}
}
static uint8_t *vm_findmemory(vm_t *vm, uint32_t address, uint32_t size, bool write) {
if (!vm->mmu_enabled) {
if (address_end > address) {
if (address_end <= FOX32_MEMORY_RAM) {
return &vm->memory_ram[address];
}
if (
!write &&
(address >= FOX32_MEMORY_ROM_START) &&
(address -= FOX32_MEMORY_ROM_START) + size <= FOX32_MEMORY_ROM
) {
return &vm->memory_rom[address];
}
}
if (!write) {
vm->exception_operand = address;
vm_panic(vm, FOX32_ERR_FAULT_RD);
} else {
vm->exception_operand = address;
vm_panic(vm, FOX32_ERR_FAULT_WR);
}
return vm_findmemory_phys(vm, address, size, write);
} else {
mmu_page_t *virtual_page = get_present_page(address);
if (virtual_page == NULL) {
@ -459,26 +464,8 @@ static uint8_t *vm_findmemory(vm_t *vm, uint32_t address, uint32_t size, bool wr
}
uint32_t offset = address & 0x00000FFF;
uint32_t physical_address = virtual_page->physical_address | offset;
address_end = physical_address + size;
if (address_end > physical_address) {
if (address_end <= FOX32_MEMORY_RAM) {
return &vm->memory_ram[physical_address];
}
if (
!write &&
(physical_address >= FOX32_MEMORY_ROM_START) &&
(physical_address -= FOX32_MEMORY_ROM_START) + size <= FOX32_MEMORY_ROM
) {
return &vm->memory_rom[physical_address];
}
}
if (!write) {
vm->exception_operand = address;
vm_panic(vm, FOX32_ERR_FAULT_RD);
} else {
vm->exception_operand = address;
vm_panic(vm, FOX32_ERR_FAULT_WR);
}
return vm_findmemory_phys(vm, physical_address, size, write);
}
}