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Stumbles towards supporting fast tape loading.

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Right now: in a non-optional manner.
This commit is contained in:
Thomas Harte 2021-03-12 18:42:17 -05:00
parent f190a1395a
commit cd215ef521
1 changed files with 30 additions and 0 deletions
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30
Machines/AmstradCPC/AmstradCPC.cpp
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@ -24,6 +24,7 @@
#include "../MachineTypes.hpp"
#include "../../Storage/Tape/Tape.hpp"
#include "../../Storage/Tape/Parsers/Spectrum.hpp"
#include "../../ClockReceiver/ForceInline.hpp"
#include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
@ -915,6 +916,30 @@ template <bool has_fdc> class ConcreteMachine:
uint16_t address = cycle.address ? *cycle.address : 0x0000;
switch(cycle.operation) {
case CPU::Z80::PartialMachineCycle::ReadOpcode:
if(address == tape_read_byte_address && read_pointers_[0] == roms_[ROMType::OS].data()) {
using Parser = Storage::Tape::ZXSpectrum::Parser;
Parser parser(Parser::MachineType::AmstradCPC);
parser.set_cpc_read_speed(read_pointers_[tape_speed_value_address >> 14][tape_speed_value_address & 16383]);
const auto byte = parser.get_byte(tape_player_.get_tape());
auto flags = z80_.get_value_of_register(CPU::Z80::Register::Flags);
if(byte) {
z80_.set_value_of_register(CPU::Z80::Register::A, *byte);
flags |= CPU::Z80::Flag::Carry;
} else {
// TODO: return tape player to previous state and decline to serve.
z80_.set_value_of_register(CPU::Z80::Register::A, 0);
flags &= ~CPU::Z80::Flag::Carry;
}
z80_.set_value_of_register(CPU::Z80::Register::Flags, flags);
// RET.
*cycle.value = 0xc9;
break;
}
[[fallthrough]];
case CPU::Z80::PartialMachineCycle::Read:
*cycle.value = read_pointers_[address >> 14][address & 16383];
break;
@ -1203,6 +1228,11 @@ template <bool has_fdc> class ConcreteMachine:
InterruptTimer interrupt_timer_;
Storage::Tape::BinaryTapePlayer tape_player_;
// By luck these values are the same between the 664 and the 6128;
// therefore the has_fdc template flag is sufficient to locate them.
static constexpr uint16_t tape_read_byte_address = has_fdc ? 0x2b20 : 0x29b0;
static constexpr uint16_t tape_speed_value_address = has_fdc ? 0xb1e7 : 0xbc8f;
HalfCycles clock_offset_;
HalfCycles crtc_counter_;
HalfCycles half_cycles_since_ay_update_;