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Slim down the flow controller.

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This commit is contained in:
Thomas Harte 2023-11-01 14:49:30 -04:00
parent 097b328075
commit bc095bb9ce
2 changed files with 38 additions and 41 deletions
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60
InstructionSets/x86/Implementation/PerformImplementation.hpp
View File

@ -821,14 +821,16 @@ void not_(IntT &destination) {
destination = ~destination;
}
template <typename IntT, typename RegistersT, typename FlowControllerT>
void call_relative(IntT offset, RegistersT &registers, FlowControllerT &flow_controller) {
flow_controller.call(registers.ip() + offset);
template <typename IntT, typename RegistersT, typename MemoryT, typename FlowControllerT>
void call_relative(IntT offset, RegistersT &registers, MemoryT &memory, FlowControllerT &flow_controller) {
push<uint16_t, false>(registers.ip(), memory, registers);
flow_controller.jump(registers.ip() + offset);
}
template <typename IntT, typename FlowControllerT>
void call_absolute(IntT target, FlowControllerT &flow_controller) {
flow_controller.call(target);
template <typename IntT, typename RegistersT, typename MemoryT, typename FlowControllerT>
void call_absolute(IntT target, RegistersT &registers, MemoryT &memory, FlowControllerT &flow_controller) {
push<uint16_t, false>(registers.ip(), memory, registers);
flow_controller.jump(target);
}
template <typename IntT, typename FlowControllerT>
@ -843,11 +845,18 @@ void call_far(InstructionT &instruction,
MemoryT &memory
) {
// TODO: eliminate 16-bit assumption below.
uint16_t source_address = 0;
const Source source_segment = instruction.data_segment();
memory.preauthorise_stack_write(sizeof(uint16_t) * 2);
uint16_t source_address;
const auto pointer = instruction.destination();
switch(pointer.source()) {
default:
case Source::Immediate: flow_controller.call(instruction.segment(), instruction.offset()); return;
case Source::Immediate:
push<uint16_t, true>(registers.cs(), memory, registers);
push<uint16_t, true>(registers.ip(), memory, registers);
flow_controller.jump(instruction.segment(), instruction.offset());
return;
case Source::Indirect:
source_address = address<model, Source::Indirect, uint16_t, AccessType::Read>(instruction, pointer, registers, memory);
@ -860,13 +869,14 @@ void call_far(InstructionT &instruction,
break;
}
const Source source_segment = instruction.data_segment();
memory.preauthorise_read(source_segment, source_address, sizeof(uint16_t) * 2);
push<uint16_t, true>(registers.cs(), memory, registers);
push<uint16_t, true>(registers.ip(), memory, registers);
// TODO: preauthorise reads.
const uint16_t offset = memory.template access<uint16_t, AccessType::Read>(source_segment, source_address);
const uint16_t offset = memory.template access<uint16_t, AccessType::PreauthorisedRead>(source_segment, source_address);
source_address += 2;
const uint16_t segment = memory.template access<uint16_t, AccessType::Read>(source_segment, source_address);
flow_controller.call(segment, offset);
const uint16_t segment = memory.template access<uint16_t, AccessType::PreauthorisedRead>(source_segment, source_address);
flow_controller.jump(segment, offset);
}
template <Model model, typename InstructionT, typename FlowControllerT, typename RegistersT, typename MemoryT>
@ -904,27 +914,27 @@ void jump_far(InstructionT &instruction,
template <typename FlowControllerT, typename RegistersT, typename MemoryT>
void iret(RegistersT &registers, FlowControllerT &flow_controller, MemoryT &memory, Status &status) {
// TODO: all modes other than 16-bit real mode.
memory.preauthorise_stack(sizeof(uint16_t) * 3);
registers.ip() = pop<uint16_t, true>(memory, registers);
registers.cs() = pop<uint16_t, true>(memory, registers);
memory.preauthorise_stack_read(sizeof(uint16_t) * 3);
const auto ip = pop<uint16_t, true>(memory, registers);
const auto cs = pop<uint16_t, true>(memory, registers);
status.set(pop<uint16_t, true>(memory, registers));
flow_controller.did_iret();
flow_controller.jump(cs, ip);
}
template <typename InstructionT, typename FlowControllerT, typename RegistersT, typename MemoryT>
void ret_near(InstructionT instruction, RegistersT &registers, FlowControllerT &flow_controller, MemoryT &memory) {
registers.ip() = pop<uint16_t, false>(memory, registers);
const auto ip = pop<uint16_t, false>(memory, registers);
registers.sp() += instruction.operand();
flow_controller.did_near_ret();
flow_controller.jump(ip);
}
template <typename InstructionT, typename FlowControllerT, typename RegistersT, typename MemoryT>
void ret_far(InstructionT instruction, RegistersT &registers, FlowControllerT &flow_controller, MemoryT &memory) {
memory.preauthorise_stack(sizeof(uint16_t) * 2);
registers.ip() = pop<uint16_t, true>(memory, registers);
registers.cs() = pop<uint16_t, true>(memory, registers);
memory.preauthorise_stack_read(sizeof(uint16_t) * 2);
const auto ip = pop<uint16_t, true>(memory, registers);
const auto cs = pop<uint16_t, true>(memory, registers);
registers.sp() += instruction.operand();
flow_controller.did_far_ret();
flow_controller.jump(cs, ip);
}
template <Model model, Source selector, typename InstructionT, typename MemoryT, typename RegistersT>
@ -1691,10 +1701,10 @@ template <
case Operation::NOT: Primitive::not_(source_rmw()); break; // TODO: should be a destination.
case Operation::CALLrel:
Primitive::call_relative(instruction.displacement(), registers, flow_controller);
Primitive::call_relative(instruction.displacement(), registers, memory, flow_controller);
return;
case Operation::CALLabs:
Primitive::call_absolute(destination_r(), flow_controller);
Primitive::call_absolute(destination_r(), registers, memory, flow_controller);
return;
case Operation::CALLfar:
Primitive::call_far<model>(instruction, flow_controller, registers, memory);

19
OSBindings/Mac/Clock SignalTests/8088Tests.mm
View File

@ -133,7 +133,9 @@ struct Memory {
return physical_address << 4;
}
void preauthorise_stack(uint32_t) {}
void preauthorise_stack_write(uint32_t) {}
void preauthorise_stack_read(uint32_t) {}
void preauthorise_read(InstructionSet::x86::Source, uint16_t, uint32_t) {}
// Entry point used by the flow controller so that it can mark up locations at which the flags were written,
// so that defined-flag-only masks can be applied while verifying RAM contents.
@ -233,10 +235,6 @@ class FlowController {
FlowController(Memory &memory, Registers &registers, Status &status) :
memory_(memory), registers_(registers), status_(status) {}
void did_iret() {}
void did_near_ret() {}
void did_far_ret() {}
void interrupt(int index) {
// TODO: reauthorise and possibly double fault?
const uint16_t address = static_cast<uint16_t>(index) << 2;
@ -256,17 +254,6 @@ class FlowController {
registers_.ip_ = new_ip;
}
void call(uint16_t address) {
push(registers_.ip_);
jump(address);
}
void call(uint16_t segment, uint16_t offset) {
push(registers_.cs_);
push(registers_.ip_);
jump(segment, offset);
}
void jump(uint16_t address) {
registers_.ip_ = address;
}