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Add power-on bit, moving problems forward.

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This commit is contained in:
Thomas Harte 2024-03-06 22:14:56 -05:00
parent 173fc9329a
commit 3405b3b287
1 changed files with 17 additions and 10 deletions
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27
Machines/Acorn/Archimedes/Archimedes.cpp
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@ -60,6 +60,14 @@ constexpr std::array<Zone, 0x20> zones(bool is_read) {
namespace Archimedes {
struct Interrupts {
uint8_t irq_status_a() const {
return irq_status_a_;
}
uint8_t irq_status_a_ = 0x80 | 0x10; // 0x80 = always; 0x10 = at power-on.
};
/// Primarily models the MEMC.
struct Memory {
void set_rom(const std::vector<uint8_t> &rom) {
@ -142,6 +150,7 @@ struct Memory {
template <typename IntT>
bool read(uint32_t address, IntT &source, InstructionSet::ARM::Mode mode, bool trans) {
(void)trans;
// logger.info().append("R %08x", address);
switch (read_zones_[(address >> 21) & 31]) {
case Zone::PhysicallyMappedRAM:
@ -168,7 +177,8 @@ struct Memory {
break;
case Zone::HighROM:
// TODO: require A24=A25=0, then A25=1.
// Real test is: require A24=A25=0, then A25=1.
// TODO: as above, move this test into the zones tables.
has_moved_rom_ = true;
source = high_rom<IntT>(address);
return true;
@ -178,7 +188,7 @@ struct Memory {
default: break;
case 0x10: // IRQ status A
source = 0x80;
source = ioc_.irq_status_a();
return true;
case 0x20: // IRQ status B
@ -210,6 +220,7 @@ struct Memory {
bool has_moved_rom_ = false;
std::array<uint8_t, 4*1024*1024> ram_{};
std::array<uint8_t, 2*1024*1024> rom_;
Interrupts ioc_;
template <typename IntT>
IntT &physical_ram(uint32_t address) {
@ -272,9 +283,6 @@ struct Memory {
template <typename IntT, bool is_read>
IntT *logical_ram(uint32_t address, InstructionSet::ARM::Mode mode) {
// TODO: (1) which logical page is this?
// logger.error().append("TODO: Logical RAM mapping at %08x", address);
address &= 0x1ff'ffff;
size_t page;
@ -304,6 +312,9 @@ struct Memory {
}
// TODO: eliminate switch here.
// Top of my head idea: is_read, is_user and is_os_mode make three bits, so
// keep a one-byte bitmap of permitted accesses rather than the raw protection
// level?
switch(mapping_[page].protection_level) {
case 0b00: break;
case 0b01:
@ -463,11 +474,7 @@ class ConcreteMachine:
}
// TODO: pipeline prefetch?
logger.info().append("%08x: %08x", executor_.pc(), instruction);
if(executor_.pc() == 0x03812148) {
printf("");
}
// logger.info().append("%08x: %08x", executor_.pc(), instruction);
InstructionSet::ARM::execute<arm_model>(instruction, executor_);
}
}