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80 lines
2.3 KiB
C++
80 lines
2.3 KiB
C++
//
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// SNA.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 24/04/2021.
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// Copyright © 2021 Thomas Harte. All rights reserved.
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//
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#include "SNA.hpp"
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#include "../FileHolder.hpp"
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#include "../../Analyser/Static/ZXSpectrum/Target.hpp"
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#include "../../Machines/Sinclair/ZXSpectrum/State.hpp"
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using namespace Storage::State;
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std::unique_ptr<Analyser::Static::Target> SNA::load(const std::string &file_name) {
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// Make sure the file is accessible and appropriately sized.
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FileHolder file(file_name);
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if(file.stats().st_size != 48*1024 + 0x1b) {
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return nullptr;
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}
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// SNAs are always for 48kb machines.
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using Target = Analyser::Static::ZXSpectrum::Target;
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auto result = std::make_unique<Target>();
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result->model = Target::Model::FortyEightK;
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// Prepare to populate ZX Spectrum state.
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auto *const state = new Sinclair::ZXSpectrum::State();
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result->state = std::unique_ptr<Reflection::Struct>(state);
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// Comments below: [offset] [contents]
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// 00 I
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const uint8_t i = file.get8();
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// 01 HL'; 03 DE'; 05 BC'; 07 AF'
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state->z80.registers.hl_dash = file.get16le();
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state->z80.registers.de_dash = file.get16le();
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state->z80.registers.bc_dash = file.get16le();
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state->z80.registers.af_dash = file.get16le();
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// 09 HL; 0B DE; 0D BC; 0F IY; 11 IX
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state->z80.registers.hl = file.get16le();
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state->z80.registers.de = file.get16le();
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state->z80.registers.bc = file.get16le();
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state->z80.registers.iy = file.get16le();
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state->z80.registers.ix = file.get16le();
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// 13 IFF2 (in bit 2)
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const uint8_t iff = file.get8();
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state->z80.registers.iff1 = state->z80.registers.iff2 = iff & 4;
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// 14 R
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const uint8_t r = file.get8();
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state->z80.registers.ir = uint16_t((i << 8) | r);
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// 15 AF; 17 SP; 19 interrupt mode
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state->z80.registers.flags = file.get8();
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state->z80.registers.a = file.get8();
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state->z80.registers.stack_pointer = file.get16le();
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state->z80.registers.interrupt_mode = file.get8();
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// 1A border colour
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state->video.border_colour = file.get8();
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// 1B– 48kb RAM contents
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state->ram = file.read(48*1024);
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// To establish program counter, point it to a RET that
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// I know is in the 16/48kb ROM. This avoids having to
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// try to do a pop here, given that the true program counter
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// might currently be in the ROM.
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state->z80.registers.program_counter = 0x1d83;
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return result;
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}
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