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90 lines
2.3 KiB
C++
90 lines
2.3 KiB
C++
//
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// Stack.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 08/11/2023.
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// Copyright © 2023 Thomas Harte. All rights reserved.
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//
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#ifndef Stack_hpp
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#define Stack_hpp
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#include "../AccessType.hpp"
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namespace InstructionSet::x86::Primitive {
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// The below takes a reference in order properly to handle PUSH SP,
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// which should place the value of SP after the push onto the stack.
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template <typename IntT, bool preauthorised, typename ContextT>
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void push(IntT &value, ContextT &context) {
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context.registers.sp_ -= sizeof(IntT);
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if constexpr (preauthorised) {
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context.memory.template preauthorised_write<IntT>(Source::SS, context.registers.sp_, value);
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} else {
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context.memory.template access<IntT, AccessType::Write>(
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Source::SS,
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context.registers.sp_) = value;
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}
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context.memory.template write_back<IntT>();
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}
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template <typename IntT, bool preauthorised, typename ContextT>
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IntT pop(ContextT &context) {
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const auto value = context.memory.template access<IntT, preauthorised ? AccessType::PreauthorisedRead : AccessType::Read>(
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Source::SS,
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context.registers.sp_);
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context.registers.sp_ += sizeof(IntT);
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return value;
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}
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template <typename ContextT>
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void sahf(
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uint8_t &ah,
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ContextT &context
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) {
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/*
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EFLAGS(SF:ZF:0:AF:0:PF:1:CF) ← AH;
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*/
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context.flags.template set_from<uint8_t, Flag::Sign>(ah);
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context.flags.template set_from<Flag::Zero>(!(ah & 0x40));
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context.flags.template set_from<Flag::AuxiliaryCarry>(ah & 0x10);
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context.flags.template set_from<Flag::ParityOdd>(!(ah & 0x04));
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context.flags.template set_from<Flag::Carry>(ah & 0x01);
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}
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template <typename ContextT>
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void lahf(
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uint8_t &ah,
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ContextT &context
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) {
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/*
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AH ← EFLAGS(SF:ZF:0:AF:0:PF:1:CF);
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*/
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ah =
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(context.flags.template flag<Flag::Sign>() ? 0x80 : 0x00) |
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(context.flags.template flag<Flag::Zero>() ? 0x40 : 0x00) |
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(context.flags.template flag<Flag::AuxiliaryCarry>() ? 0x10 : 0x00) |
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(context.flags.template flag<Flag::ParityOdd>() ? 0x00 : 0x04) |
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0x02 |
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(context.flags.template flag<Flag::Carry>() ? 0x01 : 0x00);
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}
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template <typename ContextT>
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void popf(
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ContextT &context
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) {
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context.flags.set(pop<uint16_t, false>(context));
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}
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template <typename ContextT>
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void pushf(
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ContextT &context
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) {
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uint16_t value = context.flags.get();
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push<uint16_t, false>(value, context);
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}
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}
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#endif /* Stack_hpp */
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