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CLK/Processors/Z80/Z80.hpp
Thomas Harte 4e210c5396 Added LD A, (nn).
2017-05-21 10:00:10 -04:00

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//
// Z80.hpp
// Clock Signal
//
// Created by Thomas Harte on 14/05/2017.
// Copyright © 2017 Thomas Harte. All rights reserved.
//
#ifndef Z80_hpp
#define Z80_hpp
#include <cstdint>
#include <cstdio>
#include "../MicroOpScheduler.hpp"
#include "../RegisterSizes.hpp"
namespace CPU {
namespace Z80 {
/*
The list of registers that can be accessed via @c set_value_of_register and @c set_value_of_register.
*/
enum Register {
ProgramCounter,
StackPointer,
A, Flags, AF,
B, C, BC,
D, E, DE,
H, L, HL,
ADash, FlagsDash, AFDash,
BDash, CDash, BCDash,
DDash, EDash, DEDash,
HDash, LDash, HLDash,
IXh, IXl, IX,
IYh, IYl, IY,
R, I,
};
/*
Flags as defined on the Z80; can be used to decode the result of @c get_flags or to form a value for @c set_flags.
*/
enum Flag: uint8_t {
Sign = 0x80,
Zero = 0x40,
Bit5 = 0x20,
HalfCarry = 0x10,
Bit3 = 0x08,
Parity = 0x04,
Overflow = 0x04,
Subtract = 0x02,
Carry = 0x01
};
/*!
Subclasses will be given the task of performing bus operations, allowing them to provide whatever interface they like
between a Z80 and the rest of the system. @c BusOperation lists the types of bus operation that may be requested.
@c None is reserved for internal use. It will never be requested from a subclass.
*/
enum BusOperation {
ReadOpcode = 0,
Read, Write,
Input, Output,
Interrupt,
// BusRequest, BusAcknowledge,
Internal
};
struct MachineCycle {
const BusOperation operation;
const int length;
const uint16_t *address;
uint8_t *const value;
};
struct MicroOp {
enum {
BusOperation,
DecodeOperation,
MoveToNextProgram,
Increment8,
Increment16,
Decrement8,
Decrement16,
Move8,
Move16,
AssembleAF,
DisassembleAF,
And,
Or,
Xor,
TestNZ,
TestZ,
TestNC,
TestC,
TestPO,
TestPE,
TestP,
TestM,
ADD16, ADC16, SBC16,
CP8, SUB8, SBC8, ADD8, ADC8,
ExDEHL,
LDIR,
RLA, RLCA, RRA, RRCA,
RLC, RRC, RL, RR,
SLA, SRA, SLL, SRL,
SetInstructionPage,
None
} type;
void *source;
void *destination;
MachineCycle machine_cycle;
};
/*!
@abstact An abstract base class for emulation of a 6502 processor via the curiously recurring template pattern/f-bounded polymorphism.
@discussion Subclasses should implement @c perform_bus_operation(BusOperation operation, uint16_t address, uint8_t *value) in
order to provide the bus on which the 6502 operates and @c flush(), which is called upon completion of a continuous run
of cycles to allow a subclass to bring any on-demand activities up to date.
Additional functionality can be provided by the host machine by providing a jam handler and inserting jam opcodes where appropriate;
that will cause call outs when the program counter reaches those addresses. @c return_from_subroutine can be used to exit from a
jammed state.
*/
template <class T> class Processor: public MicroOpScheduler<MicroOp> {
private:
uint8_t a_, i_, r_;
RegisterPair bc_, de_, hl_;
RegisterPair afDash_, bcDash_, deDash_, hlDash_;
RegisterPair ix_, iy_, pc_, sp_;
uint8_t sign_result_, zero_result_, bit5_result_, half_carry_flag_, bit3_result_, parity_overflow_flag_, subtract_flag_, carry_flag_;
int number_of_cycles_;
const MicroOp **program_table_;
uint8_t operation_;
RegisterPair temp16_;
uint8_t temp8_;
MicroOp **current_instruction_page_;
MicroOp *base_page_[256];
MicroOp *ed_page_[256];
MicroOp *fd_page_[256];
#define XX {MicroOp::None, 0}
#define FETCH(x, y) {MicroOp::BusOperation, nullptr, nullptr, {Read, 3, &y.full, &x}}, {MicroOp::Increment16, &y.full}
#define FETCHL(x, y) {MicroOp::BusOperation, nullptr, nullptr, {Read, 3, &y.full, &x}}
#define STOREL(x, y) {MicroOp::BusOperation, nullptr, nullptr, {Write, 3, &y.full, &x}}
#define FETCH16(x, y) FETCH(x.bytes.low, y), FETCH(x.bytes.high, y)
#define FETCH16L(x, y) FETCH(x.bytes.low, y), FETCHL(x.bytes.high, y)
#define PUSH(x) {MicroOp::Decrement16, &sp_.full}, STOREL(x.bytes.high, sp_), {MicroOp::Decrement16, &sp_.full}, STOREL(x.bytes.low, sp_)
#define POP(x) FETCHL(x.bytes.low, sp_), {MicroOp::Increment16, &sp_.full}, FETCHL(x.bytes.high, sp_), {MicroOp::Increment16, &sp_.full}
#define JP(cc) Program(FETCH16(temp16_, pc_), {MicroOp::cc}, {MicroOp::Move16, &temp16_.full, &pc_.full})
#define LD(a, b) Program({MicroOp::Move8, &b, &a})
#define LD_GROUP(r) \
LD(r, bc_.bytes.high), LD(r, bc_.bytes.low), LD(r, de_.bytes.high), LD(r, de_.bytes.low), \
LD(r, hl_.bytes.high), LD(r, hl_.bytes.low), Program(FETCHL(r, hl_)), LD(r, a_)
#define OP_GROUP(op) \
Program({MicroOp::op, &bc_.bytes.high}), Program({MicroOp::op, &bc_.bytes.low}), \
Program({MicroOp::op, &de_.bytes.high}), Program({MicroOp::op, &de_.bytes.low}), \
Program({MicroOp::op, &hl_.bytes.high}), Program({MicroOp::op, &hl_.bytes.low}), \
Program(FETCHL(temp8_, hl_), {MicroOp::op, &temp8_}), \
Program({MicroOp::op, &a_})
#define ADD16(d, s) Program(WAIT(4), WAIT(3), {MicroOp::ADD16, &s.full, &d.full})
#define ADC16(d, s) Program(WAIT(4), WAIT(3), {MicroOp::ADC16, &s.full, &d.full})
#define SBC16(d, s) Program(WAIT(4), WAIT(3), {MicroOp::SBC16, &s.full, &d.full})
#define WAIT(n) {MicroOp::BusOperation, nullptr, nullptr, {Internal, n} }
#define Program(...) { __VA_ARGS__, {MicroOp::MoveToNextProgram} }
typedef MicroOp InstructionTable[256][20];
void assemble_page(MicroOp **target, InstructionTable &table) {
for(int c = 0; c < 256; c++) {
target[c] = table[c];
}
}
void assemble_ed_page(MicroOp **target) {
#define NOP_ROW() XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX, XX
static InstructionTable ed_program_table = {
NOP_ROW(), /* 0x00 */
NOP_ROW(), /* 0x10 */
NOP_ROW(), /* 0x20 */
NOP_ROW(), /* 0x30 */
NOP_ROW(), /* 0x40 */
NOP_ROW(), /* 0x50 */
NOP_ROW(), /* 0x60 */
NOP_ROW(), /* 0x70 */
NOP_ROW(), /* 0x80 */
NOP_ROW(), /* 0x90 */
NOP_ROW(), /* 0xa0 */
/* 0xb0 LDIR */ Program(FETCHL(temp8_, hl_), STOREL(temp8_, de_), WAIT(2), {MicroOp::LDIR}, WAIT(5)), /* 0xb1 CPIR */ XX,
/* 0xb2 INIR */ XX, /* 0xb3 OTIR */ XX,
XX, XX, XX, XX,
/* 0xb8 LDDR */ XX, /* 0xb9 CPDR */ XX,
/* 0xba INDR */ XX, /* 0xbb OTDR */ XX,
XX, XX, XX, XX,
NOP_ROW(), /* 0xc0 */
NOP_ROW(), /* 0xd0 */
NOP_ROW(), /* 0xe0 */
NOP_ROW(), /* 0xf0 */
};
assemble_page(target, ed_program_table);
#undef NOP_ROW
}
void assemble_base_page(MicroOp **target) {
#define INC_DEC_LD(r) \
Program({MicroOp::Increment8, &r}), \
Program({MicroOp::Decrement8, &r}), \
Program(FETCH(r, pc_))
#define INC_INC_DEC_LD(rf, r) \
Program(WAIT(2), {MicroOp::Increment16, &rf.full}), INC_DEC_LD(r)
#define DEC_INC_DEC_LD(rf, r) \
Program(WAIT(2), {MicroOp::Decrement16, &rf.full}), INC_DEC_LD(r)
static InstructionTable base_program_table = {
/* 0x00 NOP */ { {MicroOp::MoveToNextProgram} }, /* 0x01 LD BC, nn */ Program(FETCH16(bc_, pc_)),
/* 0x02 LD (BC), A */ Program(STOREL(a_, bc_)),
/* 0x03 INC BC; 0x04 INC B; 0x05 DEC B; 0x06 LD B, n */
INC_INC_DEC_LD(bc_, bc_.bytes.high),
/* 0x07 RLCA */ Program({MicroOp::RLCA}),
/* 0x08 EX AF, AF' */ XX, /* 0x09 ADD HL, BC */ ADD16(hl_, bc_),
/* 0x0a LD A, (BC) */ Program(FETCHL(a_, bc_)),
/* 0x0b DEC BC; 0x0c INC C; 0x0d DEC C; 0x0e LD C, n */
DEC_INC_DEC_LD(bc_, bc_.bytes.low),
/* 0x0f RRCA */ Program({MicroOp::RRCA}),
/* 0x10 DJNZ */ XX, /* 0x11 LD DE, nn */ Program(FETCH16(de_, pc_)),
/* 0x12 LD (DE), A */ Program(STOREL(a_, de_)),
/* 0x13 INC DE; 0x14 INC D; 0x15 DEC D; 0x16 LD D, n */
INC_INC_DEC_LD(de_, de_.bytes.high),
/* 0x17 RLA */ Program({MicroOp::RLA}),
/* 0x18 JR */ XX, /* 0x19 ADD HL, DE */ ADD16(hl_, de_),
/* 0x1a LD A, (DE) */ Program(FETCHL(a_, de_)),
/* 0x1b DEC DE; 0x1c INC E; 0x1d DEC E; 0x1e LD E, n */
DEC_INC_DEC_LD(de_, de_.bytes.low),
/* 0x1f RRA */ Program({MicroOp::RRA}),
/* 0x20 JR NZ */ XX, /* 0x21 LD HL, nn */ Program(FETCH16(hl_, pc_)),
/* 0x22 LD (nn), HL */ XX,
/* 0x23 INC HL; 0x24 INC H; 0x25 DEC H; 0x26 LD H, n */
INC_INC_DEC_LD(hl_, hl_.bytes.high),
/* 0x27 DAA */ XX,
/* 0x28 JR Z */ XX, /* 0x29 ADD HL, HL */ ADD16(hl_, hl_),
/* 0x2a LD HL, (nn) */ Program(FETCH16(temp16_, pc_), FETCH16L(hl_, temp16_)),
/* 0x2b DEC HL; 0x2c INC L; 0x2d DEC L; 0x2e LD L, n */
DEC_INC_DEC_LD(hl_, hl_.bytes.low),
/* 0x2f CPL */ XX,
/* 0x30 JR NC */ XX, /* 0x31 LD SP, nn */ Program(FETCH16(sp_, pc_)),
/* 0x32 LD (nn), A */ Program(FETCH16(temp16_, pc_), STOREL(a_, temp16_)),
/* 0x33 INC SP */ Program(WAIT(2), {MicroOp::Increment16, &sp_.full}),
/* 0x34 INC (HL) */ XX,
/* 0x35 DEC (HL) */ XX,
/* 0x36 LD (HL), n */ Program(FETCH(temp8_, pc_), STOREL(temp8_, hl_)),
/* 0x37 SCF */ XX,
/* 0x38 JR C */ XX,
/* 0x39 ADD HL, SP */ ADD16(hl_, sp_),
/* 0x3a LD A, (nn) */ Program(FETCH16(temp16_, pc_), FETCHL(a_, temp16_)),
/* 0x3b DEC SP */ Program(WAIT(2), {MicroOp::Decrement16, &sp_.full}),
/* 0x3c INC A; 0x3d DEC A; 0x3e LD A, n */
INC_DEC_LD(a_),
/* 0x3f CCF */ XX,
/* 0x40 LD B, B; 0x41 LD B, C; 0x42 LD B, D; 0x43 LD B, E; 0x44 LD B, H; 0x45 LD B, L; 0x46 LD B, (HL); 0x47 LD B, A */
LD_GROUP(bc_.bytes.high),
/* 0x48 LD C, B; 0x49 LD C, C; 0x4a LD C, D; 0x4b LD C, E; 0x4c LD C, H; 0x4d LD C, L; 0x4e LD C, (HL); 0x4f LD C, A */
LD_GROUP(bc_.bytes.low),
/* 0x50 LD D, B; 0x51 LD D, C; 0x52 LD D, D; 0x53 LD D, E; 0x54 LD D, H; 0x55 LD D, L; 0x56 LD D, (HL); 0x57 LD D, A */
LD_GROUP(de_.bytes.high),
/* 0x58 LD E, B; 0x59 LD E, C; 0x5a LD E, D; 0x5b LD E, E; 0x5c LD E, H; 0x5d LD E, L; 0x5e LD E, (HL); 0x5f LD E, A */
LD_GROUP(de_.bytes.low),
/* 0x60 LD H, B; 0x61 LD H, C; 0x62 LD H, D; 0x63 LD H, E; 0x64 LD H, H; 0x65 LD H, L; 0x66 LD H, (HL); 0x67 LD H, A */
LD_GROUP(hl_.bytes.high),
/* 0x68 LD L, B; 0x69 LD L, C; 0x6a LD L, D; 0x6b LD L, E; 0x6c LD L, H; 0x6d LD H, L; 0x6e LD L, (HL); 0x6f LD L, A */
LD_GROUP(hl_.bytes.low),
/* 0x70 LD (HL),B */ Program(STOREL(bc_.bytes.high, hl_)), /* 0x71 LD (HL), C */ Program(STOREL(bc_.bytes.low, hl_)),
/* 0x72 LD (HL),D */ Program(STOREL(de_.bytes.high, hl_)), /* 0x73 LD (HL), E */ Program(STOREL(de_.bytes.low, hl_)),
/* 0x74 LD (HL),H */ Program(STOREL(hl_.bytes.high, hl_)), /* 0x75 LD (HL), L */ Program(STOREL(hl_.bytes.low, hl_)),
/* 0x76 HALT */ XX, /* 0x77 LD (HL), A */ Program(STOREL(a_, hl_)),
/* 0x78 LD A, B; 0x79 LD A, C; 0x7a LD A, D; 0x7b LD A, E; 0x7c LD A, H; 0x7d LD A, L; 0x7e LD A, (HL); 0x7f LD A, A */
LD_GROUP(a_),
/* 0x80 ADD B; 0x81 ADD C; 0x82 ADD D; 0x83 ADD E; 0x84 ADD H; 0x85 ADD L; 0x86 ADD (HL); 0x87 ADD A */
OP_GROUP(ADD8),
/* 0x88 ADC B; 0x89 ADC C; 0x8a ADC D; 0x8b ADC E; 0x8c ADC H; 0x8d ADC L; 0x8e ADC (HL); 0x8f ADC A */
OP_GROUP(ADC8),
/* 0x90 SUB B; 0x91 SUB C; 0x92 SUB D; 0x93 SUB E; 0x94 SUB H; 0x95 SUB L; 0x96 SUB (HL); 0x97 SUB A */
OP_GROUP(SUB8),
/* 0x98 SBC B; 0x99 SBC C; 0x9a SBC D; 0x9b SBC E; 0x9c SBC H; 0x9d SBC L; 0x9e SBC (HL); 0x9f SBC A */
OP_GROUP(SBC8),
/* 0xa0 AND B; 0xa1 AND C; 0xa2 AND D; 0xa3 AND E; 0xa4 AND H; 0xa5 AND L; 0xa6 AND (HL); 0xa7 AND A */
OP_GROUP(And),
/* 0xa8 XOR B; 0xa9 XOR C; 0xaa XOR D; 0xab XOR E; 0xac XOR H; 0xad XOR L; 0xae XOR (HL); 0xaf XOR A */
OP_GROUP(Xor),
/* 0xb0 OR B; 0xb1 OR C; 0xb2 OR D; 0xb3 OR E; 0xb4 OR H; 0xb5 OR L; 0xb6 OR (HL); 0xb7 OR A */
OP_GROUP(Or),
/* 0xb8 CP B; 0xb9 CP C; 0xba CP D; 0xbb CP E; 0xbc CP H; 0xbd CP L; 0xbe CP (HL); 0xbf CP A */
OP_GROUP(CP8),
XX, /* 0xc0 RET NZ */
Program(POP(bc_)), /* 0xc1 POP BC */
JP(TestNZ), /* 0xc2 JP NZ */
Program(FETCH16L(temp16_, pc_), {MicroOp::Move16, &temp16_.full, &pc_.full}), /* 0xc3 JP nn */
XX, /* 0xc4 CALL NZ */
Program(WAIT(1), PUSH(bc_)), /* 0xc5 PUSH BC */
Program(FETCH(temp8_, pc_), {MicroOp::ADD8, &temp8_}), /* 0xc6 ADD A, n */
XX, /* 0xc7 RST 00h */
XX, /* 0xc8 RET Z */
Program(POP(pc_)), /* 0xc9 RET */
JP(TestZ), /* 0xca JP Z */
XX, /* 0xcb [CB page] */
XX, /* 0xcc CALL Z */
Program(FETCH16(temp16_, pc_), WAIT(1), PUSH(pc_), {MicroOp::Move16, &temp16_.full, &pc_.full}), /* 0xcd CALL */
Program(FETCH(temp8_, pc_), {MicroOp::ADC8, &temp8_}), /* 0xce ADC A, n */
XX, /* 0xcf RST 08h */
XX, /* 0xd0 RET NC */
Program(POP(de_)), /* 0xd1 POP DE */
JP(TestNC), /* 0xd2 JP NC */
XX, /* 0xd3 OUT (n), A */
XX, /* 0xd4 CALL NC */
Program(WAIT(1), PUSH(de_)), /* 0xd5 PUSH DE */
Program(FETCH(temp8_, pc_), {MicroOp::SUB8, &temp8_}), /* 0xd6 SUB n */
XX, /* 0xd7 RST 10h */
XX, /* 0xd8 RET C */
XX, /* 0xd9 EXX */
JP(TestC), /* 0xda JP C */
XX, /* 0xdb IN A, (n) */
XX, /* 0xdc CALL C */
XX, /* 0xdd [DD page] */
Program(FETCH(temp8_, pc_), {MicroOp::SBC8, &temp8_}), /* 0xde SBC A, n */
XX, /* 0xdf RST 18h */
XX, /* 0xe0 RET PO */
Program(POP(hl_)), /* 0xe1 POP HL */
JP(TestPO), /* 0xe2 JP PO */
XX, /* 0xe3 EX (SP), HL */
XX, /* 0xe4 CALL PO */
Program(WAIT(1), PUSH(hl_)), /* 0xe5 PUSH HL */
Program(FETCH(temp8_, pc_), {MicroOp::And, &temp8_}), /* 0xe6 AND n */
XX, /* 0xe7 RST 20h */
XX, /* 0xe8 RET PE */
XX, /* 0xe9 JP (HL) */
JP(TestPE), /* 0xea JP PE */
Program({MicroOp::ExDEHL}), /* 0xeb EX DE, HL */
XX, /* 0xec CALL PE */
Program({MicroOp::SetInstructionPage, ed_page_}), /* 0xed [ED page] */
Program(FETCH(temp8_, pc_), {MicroOp::Xor, &temp8_}), /* 0xee XOR n */
XX, /* 0xef RST 28h */
XX, /* 0xf0 RET p */
Program(POP(temp16_), {MicroOp::DisassembleAF}), /* 0xf1 POP AF */
JP(TestP), /* 0xf2 JP P */
XX, /* 0xf3 DI */
XX, /* 0xf4 CALL P */
Program(WAIT(1), {MicroOp::AssembleAF}, PUSH(temp16_)), /* 0xf5 PUSH AF */
Program(FETCH(temp8_, pc_), {MicroOp::Or, &temp8_}), /* 0xf6 OR n */
XX, /* 0xf7 RST 30h */
XX, /* 0xf8 RET M */
Program(WAIT(2), {MicroOp::Move16, &hl_.full, &sp_.full}), /* 0xf9 LD SP, HL */
JP(TestM), /* 0xfa JP M */
XX, /* 0xfb EI */
XX, /* 0xfc CALL M */
Program({MicroOp::SetInstructionPage, fd_page_}), /* 0xfd [FD page] */
Program(FETCH(temp8_, pc_), {MicroOp::CP8, &temp8_}), /* 0xfe CP n */
XX, /* 0xff RST 38h */
};
assemble_page(target, base_program_table);
}
void decode_operation(uint8_t operation) {
if(current_instruction_page_[operation]->type == MicroOp::None) {
printf("Unknown Z80 operation %02x!!!\n", operation);
}
schedule_program(current_instruction_page_[operation]);
}
public:
Processor() {
assemble_base_page(base_page_);
assemble_ed_page(ed_page_);
}
/*!
Runs the Z80 for a supplied number of cycles.
@discussion Subclasses must implement @c perform_machine_cycle(MachineCycle *cycle) .
If it is a read operation then @c value will be seeded with the value 0xff.
@param number_of_cycles The number of cycles to run the Z80 for.
*/
void run_for_cycles(int number_of_cycles) {
static const MicroOp fetch_decode_execute[] = {
{ MicroOp::BusOperation, nullptr, nullptr, {ReadOpcode, 4, &pc_.full, &operation_}},
{ MicroOp::DecodeOperation },
{ MicroOp::MoveToNextProgram }
};
#define checkSchedule() \
if(!scheduled_programs_[schedule_programs_read_pointer_]) {\
current_instruction_page_ = base_page_;\
schedule_program(fetch_decode_execute);\
}
number_of_cycles_ += number_of_cycles;
checkSchedule();
while(1) {
const MicroOp *operation = &scheduled_programs_[schedule_programs_read_pointer_][schedule_program_program_counter_];
schedule_program_program_counter_++;
switch(operation->type) {
case MicroOp::BusOperation:
if(number_of_cycles_ < operation->machine_cycle.length) {
return;
}
static_cast<T *>(this)->perform_machine_cycle(&operation->machine_cycle);
break;
case MicroOp::MoveToNextProgram:
move_to_next_program();
checkSchedule();
break;
case MicroOp::DecodeOperation:
pc_.full++;
decode_operation(operation_);
break;
case MicroOp::Increment16: (*(uint16_t *)operation->source)++; break;
case MicroOp::Decrement16: (*(uint16_t *)operation->source)--; break;
case MicroOp::Move8: *(uint8_t *)operation->destination = *(uint8_t *)operation->source; break;
case MicroOp::Move16: *(uint16_t *)operation->destination = *(uint16_t *)operation->source; break;
case MicroOp::AssembleAF:
temp16_.bytes.high = a_;
temp16_.bytes.low = get_flags();
break;
case MicroOp::DisassembleAF:
a_ = temp16_.bytes.high;
set_flags(temp16_.bytes.low);
break;
#pragma mark - Logical
#define set_parity(v) \
parity_overflow_flag_ = v^1;\
parity_overflow_flag_ ^= parity_overflow_flag_ >> 4;\
parity_overflow_flag_ ^= parity_overflow_flag_ << 2;\
parity_overflow_flag_ ^= parity_overflow_flag_ >> 1;\
parity_overflow_flag_ &= Flag::Parity;
case MicroOp::And:
a_ &= *(uint8_t *)operation->source;
sign_result_ = zero_result_ = bit5_result_ = bit3_result_ = a_;
parity_overflow_flag_ = 0;
set_parity(a_);
break;
case MicroOp::Or:
a_ |= *(uint8_t *)operation->source;
sign_result_ = zero_result_ = bit5_result_ = bit3_result_ = a_;
parity_overflow_flag_ = 0;
set_parity(a_);
break;
case MicroOp::Xor:
a_ ^= *(uint8_t *)operation->source;
sign_result_ = zero_result_ = bit5_result_ = bit3_result_ = a_;
parity_overflow_flag_ = 0;
set_parity(a_);
break;
#undef set_parity
#pragma mark - 8-bit arithmetic
case MicroOp::CP8: {
uint8_t value = *(uint8_t *)operation->source;
int result = a_ - value;
int halfResult = (a_&0xf) - (value&0xf);
// overflow for a subtraction is when the signs were originally
// different and the result is different again
int overflow = (value^a_) & (result^a_);
sign_result_ = // set sign and zero
zero_result_ = (uint8_t)result;
bit3_result_ = bit5_result_ = value; // set the 5 and 3 flags, which come
// from the operand atypically
carry_flag_ = (result >> 8) & Flag::Carry;
half_carry_flag_ = halfResult & Flag::HalfCarry;
parity_overflow_flag_ = (overflow&0x80) >> 5;
subtract_flag_ = Flag::Subtract;
} break;
case MicroOp::SUB8: {
uint8_t value = *(uint8_t *)operation->source;
int result = a_ - value;
int halfResult = (a_&0xf) - (value&0xf);
// overflow for a subtraction is when the signs were originally
// different and the result is different again
int overflow = (value^a_) & (result^a_);
a_ = (uint8_t)result;
sign_result_ = zero_result_ =
bit5_result_ = bit3_result_ = (uint8_t)result;
carry_flag_ = (result >> 8) & Flag::Carry;
half_carry_flag_ = halfResult & Flag::HalfCarry;
parity_overflow_flag_ = (overflow&0x80) >> 5;
subtract_flag_ = Flag::Subtract;
} break;
case MicroOp::SBC8: {
uint8_t value = *(uint8_t *)operation->source;
int result = a_ - value - carry_flag_;
int halfResult = (a_&0xf) - (value&0xf) - carry_flag_;
// overflow for a subtraction is when the signs were originally
// different and the result is different again
int overflow = (value^a_) & (result^a_);
a_ = (uint8_t)result;
sign_result_ = zero_result_ =
bit5_result_ = bit3_result_ = (uint8_t)result;
carry_flag_ = (result >> 8) & Flag::Carry;
half_carry_flag_ = halfResult & Flag::HalfCarry;
parity_overflow_flag_ = (overflow&0x80) >> 5;
subtract_flag_ = Flag::Subtract;
} break;
case MicroOp::ADD8: {
uint8_t value = *(uint8_t *)operation->source;
int result = a_ + value;
int halfResult = (a_&0xf) + (value&0xf);
// overflow for addition is when the signs were originally
// the same and the result is different
int overflow = ~(value^a_) & (result^a_);
a_ = (uint8_t)result;
sign_result_ = zero_result_ =
bit3_result_ = bit5_result_ = (uint8_t)result;
carry_flag_ = (result >> 8) & Flag::Carry;
half_carry_flag_ = halfResult & Flag::HalfCarry;
parity_overflow_flag_ = (overflow&0x80) >> 5;
subtract_flag_ = 0;
} break;
case MicroOp::ADC8: {
uint8_t value = *(uint8_t *)operation->source;
int result = a_ + value + carry_flag_;
int halfResult = (a_&0xf) + (value&0xf) + carry_flag_;
// overflow for addition is when the signs were originally
// the same and the result is different
int overflow = ~(value^a_) & (result^a_);
a_ = (uint8_t)result;
sign_result_ = zero_result_ =
bit5_result_ = bit3_result_ = (uint8_t)result;
carry_flag_ = (result >> 8) & Flag::Carry;
half_carry_flag_ = halfResult & Flag::HalfCarry;
parity_overflow_flag_ = (overflow&0x80) >> 5;
subtract_flag_ = 0;
} break;
case MicroOp::Increment8: {
uint8_t value = *(uint8_t *)operation->source;
int result = value + 1;
// with an increment, overflow occurs if the sign changes from
// positive to negative
int overflow = (value ^ result) & ~value;
int half_result = (value&0xf) + 1;
*(uint8_t *)operation->source = (uint8_t)result;
// sign, zero and 5 & 3 are set directly from the result
bit5_result_ = bit3_result_ = sign_result_ = zero_result_ = (uint8_t)result;
half_carry_flag_ = half_result & Flag::HalfCarry;
parity_overflow_flag_ = (overflow >> 5)&Flag::Overflow;
subtract_flag_ = 0;
} break;
case MicroOp::Decrement8: {
uint8_t value = *(uint8_t *)operation->source;
int result = value - 1;
// with an increment, overflow occurs if the sign changes from
// positive to negative
int overflow = (value ^ result) & ~value;
int half_result = (value&0xf) - 1;
*(uint8_t *)operation->source = (uint8_t)result;
// sign, zero and 5 & 3 are set directly from the result
bit5_result_ = bit3_result_ = sign_result_ = zero_result_ = (uint8_t)result;
half_carry_flag_ = half_result & Flag::HalfCarry;
parity_overflow_flag_ = (overflow >> 5)&Flag::Overflow;
subtract_flag_ = Flag::Subtract;
} break;
#pragma mark - 16-bit arithmetic
case MicroOp::ADD16: {
uint16_t sourceValue = *(uint16_t *)operation->source;
uint16_t destinationValue = *(uint16_t *)operation->destination;
int result = sourceValue + destinationValue;
int halfResult = (sourceValue&0xfff) + (destinationValue&0xfff);
bit3_result_ = bit5_result_ = (uint8_t)(result >> 8);
carry_flag_ = (result >> 16) & Flag::Carry;
half_carry_flag_ = (halfResult >> 8) & Flag::HalfCarry;
subtract_flag_ = 0;
*(uint16_t *)operation->destination = (uint16_t)result;
} break;
case MicroOp::ADC16: {
uint16_t sourceValue = *(uint16_t *)operation->source;
uint16_t destinationValue = *(uint16_t *)operation->destination;
int result = sourceValue + destinationValue + carry_flag_;
int halfResult = (sourceValue&0xfff) + (destinationValue&0xfff) + carry_flag_;
int overflow = (result ^ destinationValue) & ~(destinationValue ^ sourceValue);
bit5_result_ =
bit3_result_ =
sign_result_ = (uint8_t)(result >> 8);
zero_result_ = (uint8_t)(result | sign_result_);
subtract_flag_ = 0;
carry_flag_ = result >> 16;
half_carry_flag_ = (halfResult >> 8) & Flag::HalfCarry;
parity_overflow_flag_ = (overflow & 0x8000) >> 13;
*(uint16_t *)operation->destination = (uint16_t)result;
} break;
case MicroOp::SBC16: {
uint16_t sourceValue = *(uint16_t *)operation->source;
uint16_t destinationValue = *(uint16_t *)operation->destination;
int result = destinationValue - sourceValue - carry_flag_;
int halfResult = (destinationValue&0xfff) - (sourceValue&0xfff) - carry_flag_;
// subtraction, so parity rules are:
// signs of operands were different,
// sign of result is different
int overflow = (result ^ destinationValue) & (sourceValue ^ destinationValue);
bit5_result_ =
bit3_result_ =
sign_result_ = (uint8_t)(result >> 8);
zero_result_ = (uint8_t)(result | sign_result_);
subtract_flag_ = Flag::Subtract;
carry_flag_ = result >> 16;
half_carry_flag_ = (halfResult >> 8) & Flag::HalfCarry;
parity_overflow_flag_ = (overflow & 0x8000) >> 13;
*(uint16_t *)operation->destination = (uint16_t)result;
} break;
case MicroOp::TestNZ: if(!zero_result_) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestZ: if(zero_result_) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestNC: if(carry_flag_) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestC: if(!carry_flag_) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestPO: if(parity_overflow_flag_) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestPE: if(!parity_overflow_flag_) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestP: if(sign_result_ & 0x80) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::TestM: if(!(sign_result_ & 0x80)) { move_to_next_program(); checkSchedule(); } break;
case MicroOp::ExDEHL: {
uint16_t temp = de_.full;
de_.full = hl_.full;
hl_.full = temp;
} break;
#pragma mark - Repetition group
case MicroOp::LDIR: {
bc_.full--;
de_.full++;
hl_.full++;
bit3_result_ = bit5_result_ = a_ + temp8_;
subtract_flag_ = 0;
half_carry_flag_ = 0;
if(bc_.full) {
parity_overflow_flag_ = Flag::Parity;
pc_.full -= 2;
} else {
parity_overflow_flag_ = 0;
move_to_next_program();
checkSchedule();
}
} break;
#pragma mark - Rotation
case MicroOp::RLA: {
uint8_t new_carry = a_ >> 7;
a_ = (uint8_t)((a_ << 1) | carry_flag_);
bit3_result_ = bit5_result_ = a_;
carry_flag_ = new_carry;
subtract_flag_ = half_carry_flag_ = 0;
} break;
case MicroOp::RLCA: {
uint8_t new_carry = a_ >> 7;
a_ = (uint8_t)((a_ << 1) | new_carry);
bit3_result_ = bit5_result_ = a_;
carry_flag_ = new_carry;
subtract_flag_ = half_carry_flag_ = 0;
} break;
case MicroOp::RRA: {
uint8_t newCarry = a_ & 1;
a_ = (uint8_t)((a_ >> 1) | (carry_flag_ << 7));
bit3_result_ = bit5_result_ = a_;
carry_flag_ = newCarry;
subtract_flag_ = half_carry_flag_ = 0;
} break;
case MicroOp::RRCA: {
uint8_t newCarry = a_ & 1;
a_ = (uint8_t)((a_ >> 1) | (newCarry << 7));
bit5_result_ = bit3_result_ = a_;
carry_flag_ = newCarry;
subtract_flag_ = half_carry_flag_ = 0;
} break;
#pragma mark - Internal bookkeeping
case MicroOp::SetInstructionPage:
schedule_program(fetch_decode_execute);
current_instruction_page_ = (CPU::Z80::MicroOp **)operation->source;
break;
default:
// printf("Unhandled Z80 operation %d\n", operation->type);
return;
}
}
}
/*!
Called to announce the end of a run_for_cycles period, allowing deferred work to take place.
Users of the Z80 template may override this.
*/
void flush() {}
int perform_machine_cycle(const MachineCycle *cycle) {
return 0;
}
/*!
Gets the flags register.
@see set_flags
@returns The current value of the flags register.
*/
uint8_t get_flags() {
return
(sign_result_ & Flag::Sign) |
(zero_result_ ? 0 : Flag::Zero) |
(bit5_result_ & Flag::Bit5) |
half_carry_flag_ |
(bit3_result_ & Flag::Bit3) |
parity_overflow_flag_ |
subtract_flag_ |
carry_flag_;
}
/*!
Sets the flags register.
@see set_flags
@param flags The new value of the flags register.
*/
void set_flags(uint8_t flags) {
sign_result_ = flags;
zero_result_ = (flags & Flag::Zero) ^ Flag::Zero;
bit5_result_ = flags;
half_carry_flag_ = flags & Flag::HalfCarry;
bit3_result_ = flags;
parity_overflow_flag_ = flags & Flag::Parity;
subtract_flag_ = flags & Flag::Subtract;
carry_flag_ = flags & Flag::Carry;
}
/*!
Gets the value of a register.
@see set_value_of_register
@param r The register to set.
@returns The value of the register. 8-bit registers will be returned as unsigned.
*/
uint16_t get_value_of_register(Register r) {
switch (r) {
case Register::ProgramCounter: return pc_.full;
case Register::StackPointer: return sp_.full;
case Register::A: return a_;
case Register::Flags: return get_flags();
case Register::AF: return (uint16_t)((a_ << 8) | get_flags());
case Register::B: return bc_.bytes.high;
case Register::C: return bc_.bytes.low;
case Register::BC: return bc_.full;
case Register::D: return de_.bytes.high;
case Register::E: return de_.bytes.low;
case Register::DE: return de_.full;
case Register::H: return hl_.bytes.high;
case Register::L: return hl_.bytes.low;
case Register::HL: return hl_.full;
case Register::ADash: return afDash_.bytes.high;
case Register::FlagsDash: return afDash_.bytes.low;
case Register::AFDash: return afDash_.full;
case Register::BDash: return bcDash_.bytes.high;
case Register::CDash: return bcDash_.bytes.low;
case Register::BCDash: return bcDash_.full;
case Register::DDash: return deDash_.bytes.high;
case Register::EDash: return deDash_.bytes.low;
case Register::DEDash: return deDash_.full;
case Register::HDash: return hlDash_.bytes.high;
case Register::LDash: return hlDash_.bytes.low;
case Register::HLDash: return hlDash_.full;
case Register::IXh: return ix_.bytes.high;
case Register::IXl: return ix_.bytes.low;
case Register::IX: return ix_.full;
case Register::IYh: return iy_.bytes.high;
case Register::IYl: return iy_.bytes.low;
case Register::IY: return iy_.full;
case Register::R: return r_;
case Register::I: return i_;
default: return 0;
}
}
/*!
Sets the value of a register.
@see get_value_of_register
@param r The register to set.
@param value The value to set. If the register is only 8 bit, the value will be truncated.
*/
void set_value_of_register(Register r, uint16_t value) {
switch (r) {
case Register::ProgramCounter: pc_.full = value; break;
case Register::StackPointer: sp_.full = value; break;
case Register::A: a_ = (uint8_t)value; break;
case Register::AF: a_ = (uint8_t)(value >> 8); // deliberate fallthrough...
case Register::Flags: set_flags((uint8_t)value); break;
case Register::B: bc_.bytes.high = (uint8_t)value; break;
case Register::C: bc_.bytes.low = (uint8_t)value; break;
case Register::BC: bc_.full = value; break;
case Register::D: de_.bytes.high = (uint8_t)value; break;
case Register::E: de_.bytes.low = (uint8_t)value; break;
case Register::DE: de_.full = value; break;
case Register::H: hl_.bytes.high = (uint8_t)value; break;
case Register::L: hl_.bytes.low = (uint8_t)value; break;
case Register::HL: hl_.full = value; break;
case Register::ADash: afDash_.bytes.high = (uint8_t)value; break;
case Register::FlagsDash: afDash_.bytes.low = (uint8_t)value; break;
case Register::AFDash: afDash_.full = value; break;
case Register::BDash: bcDash_.bytes.high = (uint8_t)value; break;
case Register::CDash: bcDash_.bytes.low = (uint8_t)value; break;
case Register::BCDash: bcDash_.full = value; break;
case Register::DDash: deDash_.bytes.high = (uint8_t)value; break;
case Register::EDash: deDash_.bytes.low = (uint8_t)value; break;
case Register::DEDash: deDash_.full = value; break;
case Register::HDash: hlDash_.bytes.high = (uint8_t)value; break;
case Register::LDash: hlDash_.bytes.low = (uint8_t)value; break;
case Register::HLDash: hlDash_.full = value; break;
case Register::IXh: ix_.bytes.high = (uint8_t)value; break;
case Register::IXl: ix_.bytes.low = (uint8_t)value; break;
case Register::IX: ix_.full = value; break;
case Register::IYh: iy_.bytes.high = (uint8_t)value; break;
case Register::IYl: iy_.bytes.low = (uint8_t)value; break;
case Register::IY: iy_.full = value; break;
case Register::R: r_ = (uint8_t)value; break;
case Register::I: i_ = (uint8_t)value; break;
default: break;
}
}
};
}
}
#endif /* Z80_hpp */
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