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Factors out the language card memory selection logic.

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This commit is contained in:
Thomas Harte 2020-10-22 21:01:12 -04:00
parent 817f93a490
commit 410c99de54
3 changed files with 89 additions and 36 deletions
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49
Machines/Apple/AppleII/AppleII.cpp
View File

@ -21,6 +21,7 @@
#include "Card.hpp"
#include "DiskIICard.hpp"
#include "LanguageCard.hpp"
#include "Video.hpp"
#include "../../../Analyser/Static/AppleII/Target.hpp"
@ -188,24 +189,20 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
}
// MARK: - The language card.
struct {
bool bank1 = false;
bool read = false;
bool pre_write = false;
bool write = false;
} language_card_;
bool has_language_card_ = true;
LanguageCard<ConcreteMachine> language_card_;
friend LanguageCard<ConcreteMachine>;
void set_language_card_paging() {
uint8_t *const ram = alternative_zero_page_ ? aux_ram_ : ram_;
uint8_t *const rom = is_iie() ? &rom_[3840] : rom_.data();
const auto state = language_card_.state();
page(0xd0, 0xe0,
language_card_.read ? &ram[language_card_.bank1 ? 0xd000 : 0xc000] : rom,
language_card_.write ? nullptr : &ram[language_card_.bank1 ? 0xd000 : 0xc000]);
state.read ? &ram[state.bank1 ? 0xd000 : 0xc000] : rom,
state.write ? nullptr : &ram[state.bank1 ? 0xd000 : 0xc000]);
page(0xe0, 0x100,
language_card_.read ? &ram[0xe000] : &rom[0x1000],
language_card_.write ? nullptr : &ram[0xe000]);
state.read ? &ram[0xe000] : &rom[0x1000],
state.write ? nullptr : &ram[0xe000]);
}
// MARK - The IIe's ROM controls.
@ -320,7 +317,8 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
video_bus_handler_(ram_, aux_ram_),
video_(video_bus_handler_),
audio_toggle_(audio_queue_),
speaker_(audio_toggle_) {
speaker_(audio_toggle_),
language_card_(*this) {
// The system's master clock rate.
constexpr float master_clock = 14318180.0;
@ -534,8 +532,8 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
// The IIe-only state reads follow...
#define IIeSwitchRead(s) *value = get_keyboard_input(); if(is_iie()) *value = (*value & 0x7f) | (s ? 0x80 : 0x00);
case 0xc011: IIeSwitchRead(language_card_.bank1); break;
case 0xc012: IIeSwitchRead(language_card_.read); break;
case 0xc011: IIeSwitchRead(language_card_.state().bank1); break;
case 0xc012: IIeSwitchRead(language_card_.state().read); break;
case 0xc013: IIeSwitchRead(read_auxiliary_memory_); break;
case 0xc014: IIeSwitchRead(write_auxiliary_memory_); break;
case 0xc015: IIeSwitchRead(internal_CX_rom_); break;
@ -681,28 +679,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
case 0xc081: case 0xc085: case 0xc089: case 0xc08d:
case 0xc082: case 0xc086: case 0xc08a: case 0xc08e:
case 0xc083: case 0xc087: case 0xc08b: case 0xc08f:
// Quotes below taken from Understanding the Apple II, p. 5-28 and 5-29.
// "A3 controls the 4K bank selection"
language_card_.bank1 = (address&8);
// "Access to $C080, $C083, $C084, $0087, $C088, $C08B, $C08C, or $C08F sets the READ ENABLE flip-flop"
// (other accesses reset it)
language_card_.read = !(((address&2) >> 1) ^ (address&1));
// "The WRITE ENABLE' flip-flop is reset by an odd read access to the $C08X range when the PRE-WRITE flip-flop is set."
if(language_card_.pre_write && isReadOperation(operation) && (address&1)) language_card_.write = false;
// "[The WRITE ENABLE' flip-flop] is set by an even access in the $C08X range."
if(!(address&1)) language_card_.write = true;
// ("Any other type of access causes the WRITE ENABLE' flip-flop to hold its current state.")
// "The PRE-WRITE flip-flop is set by an odd read access in the $C08X range. It is reset by an even access or a write access."
language_card_.pre_write = isReadOperation(operation) ? (address&1) : false;
// Apply whatever the net effect of all that is to the memory map.
set_language_card_paging();
language_card_.access(address, isReadOperation(operation));
break;
}

74
Machines/Apple/AppleII/LanguageCard.hpp Normal file
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@ -0,0 +1,74 @@
//
// LanguageCard.hpp
// Clock Signal
//
// Created by Thomas Harte on 22/10/2020.
// Copyright © 2020 Thomas Harte. All rights reserved.
//
#ifndef LanguageCard_h
#define LanguageCard_h
namespace Apple {
namespace II {
template <typename Machine> class LanguageCard {
public:
struct State {
/// Indicates which 4kb chunk of RAM should be visible at $Dxxx if RAM is visible at all.
bool bank1 = false;
/// @c true indicates that RAM should be readable in the range $D000–$FFFF;
/// @c indicates ROM should be readable.
bool read = false;
/// @c true indicates that ROM is selected for 'writing' in the range $D000–$FFFF (i.e. writes are a no-op);
/// @c false indicates that RAM is selected for writing.
bool write = false;
/// Contains the state of the internal pre-write flip flop; it does not directly affect the current memory map.
bool pre_write = false;
};
LanguageCard(Machine &machine) : machine_(machine) {}
/// Should be used by an owner to forward any access to $c08x.
void access(uint16_t address, bool is_read) {
// Quotes below taken from Understanding the Apple II, p. 5-28 and 5-29.
// "A3 controls the 4K bank selection"
state_.bank1 = address & 8;
// "Access to $C080, $C083, $C084, $0087, $C088, $C08B, $C08C, or $C08F sets the READ ENABLE flip-flop"
// (other accesses reset it)
state_.read = !(((address&2) >> 1) ^ (address&1));
// "The WRITE ENABLE' flip-flop is reset by an odd read access to the $C08X range when the PRE-WRITE flip-flop is set."
if(state_.pre_write && is_read && (address&1)) state_.write = false;
// "[The WRITE ENABLE' flip-flop] is set by an even access in the $C08X range."
if(!(address&1)) state_.write = true;
// ("Any other type of access causes the WRITE ENABLE' flip-flop to hold its current state.")
// "The PRE-WRITE flip-flop is set by an odd read access in the $C08X range. It is reset by an even access or a write access."
state_.pre_write = is_read ? (address&1) : false;
// Apply whatever the net effect of all that is to the memory map.
machine_.set_language_card_paging();
}
/// Provides read-only access to the current language card switch state.
const State &state() {
return state_;
}
private:
Machine &machine_;
State state_;
};
}
}
#endif /* LanguageCard_h */

2
OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
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@ -1809,6 +1809,7 @@
4BEF6AA81D35CE9E00E73575 /* DigitalPhaseLockedLoopBridge.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DigitalPhaseLockedLoopBridge.h; sourceTree = "<group>"; };
4BEF6AA91D35CE9E00E73575 /* DigitalPhaseLockedLoopBridge.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = DigitalPhaseLockedLoopBridge.mm; sourceTree = "<group>"; };
4BEF6AAB1D35D1C400E73575 /* DPLLTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DPLLTests.swift; sourceTree = "<group>"; };
4BF40A5525424C770033EA39 /* LanguageCard.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = LanguageCard.hpp; sourceTree = "<group>"; };
4BF437EC209D0F7E008CBD6B /* SegmentParser.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = SegmentParser.cpp; sourceTree = "<group>"; };
4BF437ED209D0F7E008CBD6B /* SegmentParser.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = SegmentParser.hpp; sourceTree = "<group>"; };
4BF437F0209D112F008CBD6B /* Sector.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Sector.hpp; sourceTree = "<group>"; };
@ -3746,6 +3747,7 @@
4BCE004B227CE8CA000CA200 /* Card.hpp */,
4BCE004C227CE8CA000CA200 /* DiskIICard.hpp */,
4BCE004F227CE8CA000CA200 /* Video.hpp */,
4BF40A5525424C770033EA39 /* LanguageCard.hpp */,
);
path = AppleII;
sourceTree = "<group>";