mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-09-11 03:54:47 +00:00
Move to a more standard flag representation for the 8080
This commit is contained in:
Adrian.Conlon
parent
71e6902aeb
commit
675b82b5af
@ -12,6 +12,8 @@ namespace EightBit {
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static std::string state(Intel8080& cpu);
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static std::string disassemble(Intel8080& cpu);
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static std::string flag(uint8_t value, int flag, const std::string& represents);
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static std::string flags(uint8_t value);
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static std::string hex(uint8_t value);
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static std::string hex(uint16_t value);
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static std::string binary(uint8_t value);
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@ -3,7 +3,6 @@
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// Auxiliary carry logic from https://github.com/begoon/i8080-core
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#include "IntelProcessor.h"
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#include "StatusFlags.h"
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#include "InputOutput.h"
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namespace EightBit {
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@ -11,6 +10,14 @@ namespace EightBit {
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public:
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typedef std::function<void()> instruction_t;
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enum StatusBits {
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SF = Bit7,
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ZF = Bit6,
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AC = Bit4,
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PF = Bit2,
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CF = Bit0,
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};
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enum AddressingMode {
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Unknown,
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Implied, // zero bytes
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@ -31,8 +38,14 @@ namespace EightBit {
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const std::array<Instruction, 0x100>& getInstructions() const { return instructions; }
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uint8_t& A() { return a; }
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StatusFlags& F() { return f; }
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register16_t& AF() {
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af.low &= ~(Bit5 | Bit3);
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af.low |= Bit1;
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return af;
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}
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uint8_t& A() { return AF().high; }
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uint8_t& F() { return AF().low; }
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register16_t& BC() { return bc; }
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uint8_t& B() { return BC().high; }
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@ -66,15 +79,24 @@ namespace EightBit {
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std::array<Instruction, 0x100> instructions;
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uint8_t a;
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StatusFlags f;
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register16_t af;
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register16_t bc;
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register16_t de;
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register16_t hl;
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bool m_interrupt;
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void clearFlag(int flag) { F() &= ~flag; }
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void setFlag(int flag) { F() |= flag; }
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void setFlag(int flag, int condition) { setFlag(flag, condition != 0); }
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void setFlag(int flag, uint32_t condition) { setFlag(flag, condition != 0); }
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void setFlag(int flag, bool condition) { condition ? setFlag(flag) : clearFlag(flag); }
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void clearFlag(int flag, int condition) { clearFlag(flag, condition != 0); }
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void clearFlag(int flag, uint32_t condition) { clearFlag(flag, condition != 0); }
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void clearFlag(int flag, bool condition) { condition ? clearFlag(flag) : setFlag(flag); }
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int execute(uint8_t opcode);
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int execute(const Instruction& instruction) {
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@ -83,13 +105,13 @@ namespace EightBit {
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return cycles + instruction.count;
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}
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void adjustSign(uint8_t value) { F().S = ((value & Bit7) != 0); }
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void adjustZero(uint8_t value) { F().Z = !value; }
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void adjustSign(uint8_t value) { setFlag(SF, value & SF); }
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void adjustZero(uint8_t value) { clearFlag(ZF, value);}
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void adjustParity(uint8_t value) {
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static const uint8_t lookup[0x10] = { 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4 };
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auto set = (lookup[highNibble(value)] + lookup[lowNibble(value)]);
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F().P = !(set % 2);
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clearFlag(PF, set % 2);
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}
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void adjustSZP(uint8_t value) {
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@ -99,21 +121,21 @@ namespace EightBit {
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}
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void adjustAuxiliaryCarryAdd(uint8_t value, int calculation) {
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F().AC = calculateHalfCarryAdd(A(), value, calculation);
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setFlag(AC, calculateHalfCarryAdd(A(), value, calculation));
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}
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void adjustAuxiliaryCarrySub(uint8_t value, int calculation) {
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F().AC = !calculateHalfCarrySub(A(), value, calculation);
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clearFlag(AC, calculateHalfCarrySub(A(), value, calculation));
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}
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void postIncrement(uint8_t value) {
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adjustSZP(value);
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F().AC = !lowNibble(value);
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clearFlag(AC, lowNibble(value));
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}
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void postDecrement(uint8_t value) {
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adjustSZP(value);
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F().AC = lowNibble(value) != Mask4;
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setFlag(AC, lowNibble(value) != Mask4);
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}
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static Instruction INS(instruction_t method, AddressingMode mode, std::string disassembly, int cycles);
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@ -127,22 +149,22 @@ namespace EightBit {
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uint16_t subtraction = A() - value;
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adjustSZP((uint8_t)subtraction);
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adjustAuxiliaryCarrySub(value, subtraction);
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F().C = (subtraction & Bit8) != 0;
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setFlag(CF, subtraction & Bit8);
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}
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void anda(uint8_t value) {
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F().AC = (((A() | value) & Bit3) != 0);
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F().C = false;
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setFlag(AC, (A() | value) & Bit3);
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clearFlag(CF);
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adjustSZP(A() &= value);
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}
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void ora(uint8_t value) {
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F().AC = F().C = false;
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clearFlag(AC | CF);
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adjustSZP(A() |= value);
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}
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void xra(uint8_t value) {
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F().AC = F().C = false;
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clearFlag(AC | CF);
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adjustSZP(A() ^= value);
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}
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@ -151,17 +173,17 @@ namespace EightBit {
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sum.word = A() + value + carry;
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adjustAuxiliaryCarryAdd(value, sum.word);
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A() = sum.low;
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F().C = (sum.word & Bit8) != 0;
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setFlag(CF, sum.word & Bit8);
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adjustSZP(A());
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}
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void adc(uint8_t value) {
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add(value, F().C);
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add(value, F() & CF);
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}
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void dad(uint16_t value) {
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uint32_t sum = HL().word + value;
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F().C = sum > 0xffff;
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setFlag(CF, sum > 0xffff);
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HL().word = (uint16_t)sum;
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}
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@ -170,12 +192,12 @@ namespace EightBit {
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difference.word = A() - value - carry;
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adjustAuxiliaryCarrySub(value, difference.word);
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A() = difference.low;
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F().C = (difference.word & Bit8) != 0;
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setFlag(CF, difference.word & Bit8);
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adjustSZP(A());
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}
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void sbb(uint8_t value) {
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sub(value, F().C);
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sub(value, F() & CF);
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}
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void mov_m_r(uint8_t value) {
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@ -316,22 +338,12 @@ namespace EightBit {
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void push_b() { pushWord(BC()); }
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void push_d() { pushWord(DE()); }
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void push_h() { pushWord(HL()); }
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void push_psw() {
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register16_t pair;
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pair.low = F();
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pair.high = A();
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pushWord(pair);
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}
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void push_psw() { pushWord(AF()); }
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void pop_b() { popWord(BC()); }
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void pop_d() { popWord(DE()); }
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void pop_h() { popWord(HL()); }
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void pop_psw() {
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F() = pop();
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A() = pop();
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}
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void pop_psw() { popWord(AF()); }
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void xhtl() {
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auto tos = m_memory.getWord(sp.word);
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@ -354,17 +366,17 @@ namespace EightBit {
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void jmp() { jumpConditional(true); }
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void jc() { jumpConditional(F().C); }
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void jnc() { jumpConditional(!F().C); }
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void jc() { jumpConditional(F() & CF); }
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void jnc() { jumpConditional(!(F() & CF)); }
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void jz() { jumpConditional(F().Z); }
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void jnz() { jumpConditional(!F().Z); }
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void jz() { jumpConditional(F() & ZF); }
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void jnz() { jumpConditional(!(F() & ZF)); }
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void jpe() { jumpConditional(F().P); }
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void jpo() { jumpConditional(!F().P); }
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void jpe() { jumpConditional(F() & PF); }
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void jpo() { jumpConditional(!(F() & PF)); }
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void jm() { jumpConditional(F().S); }
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void jp() { jumpConditional(!F().S); }
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void jm() { jumpConditional(F() & SF); }
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void jp() { jumpConditional(!(F() & SF)); }
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void pchl() {
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pc = HL();
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@ -377,31 +389,31 @@ namespace EightBit {
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call();
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}
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void cc() { if (callConditional(F().C)) cycles += 6; }
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void cnc() { if (callConditional(!F().C)) cycles += 6; }
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void cc() { if (callConditional(F() & CF)) cycles += 6; }
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void cnc() { if (callConditional(!(F() & CF))) cycles += 6; }
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void cpe() { if (callConditional(F().P)) cycles += 6; }
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void cpo() { if (callConditional(!F().P)) cycles += 6; }
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void cpe() { if (callConditional(F() & PF)) cycles += 6; }
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void cpo() { if (callConditional(!(F() & PF))) cycles += 6; }
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void cz() { if (callConditional(F().Z)) cycles += 6; }
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void cnz() { if (callConditional(!F().Z)) cycles += 6; }
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void cz() { if (callConditional(F() & ZF)) cycles += 6; }
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void cnz() { if (callConditional(!(F() & ZF))) cycles += 6; }
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void cm() { if (callConditional(F().S)) cycles += 6; }
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void cp() { if (callConditional(!F().S)) cycles += 6; }
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void cm() { if (callConditional(F() & SF)) cycles += 6; }
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void cp() { if (callConditional(!(F() & SF))) cycles += 6; }
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// return
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void rc() { if (returnConditional(F().C)) cycles += 6; }
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void rnc() { if (returnConditional(!F().C)) cycles += 6; }
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void rc() { if (returnConditional(F() & CF)) cycles += 6; }
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void rnc() { if (returnConditional(!(F() & CF))) cycles += 6; }
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void rz() { if (returnConditional(F().Z)) cycles += 6; }
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void rnz() { if (returnConditional(!F().Z)) cycles += 6; }
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void rz() { if (returnConditional(F() & ZF)) cycles += 6; }
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void rnz() { if (returnConditional(!(F() & ZF))) cycles += 6; }
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void rpe() { if (returnConditional(F().P)) cycles += 6; }
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void rpo() { if (returnConditional(!F().P)) cycles += 6; }
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void rpe() { if (returnConditional(F() & PF)) cycles += 6; }
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void rpo() { if (returnConditional(!(F() & PF))) cycles += 6; }
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void rm() { if (returnConditional(F().S)) cycles += 6; }
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void rp() { if (returnConditional(!F().S)) cycles += 6; }
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void rm() { if (returnConditional(F() & SF)) cycles += 6; }
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void rp() { if (returnConditional(!(F() & SF))) cycles += 6; }
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// restart
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@ -594,49 +606,49 @@ namespace EightBit {
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void rlc() {
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auto carry = A() & Bit7;
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A() <<= 1;
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A() |= carry >> 7;
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F().C = carry != 0;
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carry ? A() |= Bit0 : A() &= ~Bit0;
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setFlag(CF, carry);
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}
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void rrc() {
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auto carry = A() & 1;
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auto carry = A() & Bit0;
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A() >>= 1;
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A() |= carry << 7;
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F().C = carry != 0;
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carry ? A() |= Bit7 : A() &= ~Bit7;
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setFlag(CF, carry);
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}
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void ral() {
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auto carry = A() & Bit7;
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A() <<= 1;
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A() |= (uint8_t)F().C;
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F().C = carry != 0;
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A() |= (F() & CF);
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setFlag(CF, carry);
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}
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void rar() {
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auto carry = A() & 1;
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A() >>= 1;
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A() |= F().C << 7;
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F().C = carry != 0;
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A() |= (F() & CF) << 7;
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setFlag(CF, carry);
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}
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// specials
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void cma() { A() ^= Mask8; }
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void stc() { F().C = true; }
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void cmc() { F().C = !F().C; }
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void stc() { setFlag(CF); }
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void cmc() { clearFlag(CF, F() & CF); }
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void daa() {
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auto carry = F().C;
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auto carry = F() & CF;
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uint8_t addition = 0;
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if (F().AC || lowNibble(A()) > 9) {
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if ((F() & AC) || lowNibble(A()) > 9) {
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addition = 0x6;
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}
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if (F().C || highNibble(A()) > 9 || (highNibble(A()) >= 9 && lowNibble(A()) > 9)) {
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if ((F() & CF) || highNibble(A()) > 9 || (highNibble(A()) >= 9 && lowNibble(A()) > 9)) {
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addition |= 0x60;
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carry = true;
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}
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add(addition);
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F().C = carry;
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setFlag(CF, carry);
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}
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// input/output
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@ -1,72 +0,0 @@
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#pragma once
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#include <string>
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#include <cstdint>
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namespace EightBit {
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struct StatusFlags {
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bool S;
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bool Z;
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bool AC;
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bool P;
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bool C;
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enum StatusBits {
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Sign = 0x80, // S
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Zero = 0x40, // Z
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AuxiliaryCarry = 0x10, // AC
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Parity = 0x4, // Z
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Carry = 0x1, // S
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};
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StatusFlags(uint8_t value) {
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S = (value & StatusBits::Sign) != 0;
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Z = (value & StatusBits::Zero) != 0;
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AC = (value & StatusBits::AuxiliaryCarry) != 0;
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P = (value & StatusBits::Parity) != 0;
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C = (value & StatusBits::Carry) != 0;
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}
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operator uint8_t() const {
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uint8_t flags = 0;
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if (S)
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flags |= StatusBits::Sign;
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if (Z)
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flags |= StatusBits::Zero;
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flags &= ~0x20; // Reserved off
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if (AC)
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flags |= StatusBits::AuxiliaryCarry;
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flags &= ~0x8; // Reserved off
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if (P)
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flags |= StatusBits::Parity;
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flags |= 0x2; // Reserved on
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if (C)
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flags |= StatusBits::Carry;
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return flags;
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}
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operator std::string() const {
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std::string returned;
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returned += S ? "S" : "-";
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returned += Z ? "Z" : "-";
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returned += "0";
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returned += AC ? "A" : "-";
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returned += "0";
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returned += P ? "P" : "-";
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returned += "1";
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returned += C ? "C" : "-";
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return returned;
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}
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};
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}
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@ -7,7 +7,6 @@
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#include "Memory.h"
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#include "Intel8080.h"
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#include "StatusFlags.h"
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EightBit::Disassembler::Disassembler() {
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}
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@ -35,7 +34,7 @@ std::string EightBit::Disassembler::state(Intel8080& cpu) {
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<< "PC=" << hex(pc.word)
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<< " "
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<< "SP=" << hex(sp.word)
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<< " " << "A=" << hex(a) << " " << "F=" << (std::string)f
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<< " " << "A=" << hex(a) << " " << "F=" << flags(f)
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<< " " << "B=" << hex(b) << " " << "C=" << hex(c)
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<< " " << "D=" << hex(d) << " " << "E=" << hex(e)
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<< " " << "H=" << hex(h) << " " << "L=" << hex(l);
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@ -87,6 +86,26 @@ std::string EightBit::Disassembler::disassemble(Intel8080& cpu) {
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return output.str();
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}
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std::string EightBit::Disassembler::flag(uint8_t value, int flag, const std::string& represents) {
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std::ostringstream output;
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output << (value & flag ? represents : "-");
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return output.str();
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}
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std::string EightBit::Disassembler::flags(uint8_t value) {
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std::ostringstream output;
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output
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<< flag(value, Intel8080::SF, "S")
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<< flag(value, Intel8080::ZF, "Z")
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<< "0"
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<< flag(value, Intel8080::AC, "A")
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<< "0"
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<< flag(value, Intel8080::PF, "P")
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<< "1"
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<< flag(value, Intel8080::CF, "C");
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return output.str();
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}
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std::string EightBit::Disassembler::hex(uint8_t value) {
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std::ostringstream output;
|
||||
output << std::hex << std::setw(2) << std::setfill('0') << (int)value;
|
||||
|
||||
@ -5,11 +5,9 @@
|
||||
#include "Disassembler.h"
|
||||
|
||||
EightBit::Intel8080::Intel8080(Memory& memory, InputOutput& ports)
|
||||
: IntelProcessor(memory),
|
||||
a(0),
|
||||
f(0),
|
||||
m_interrupt(false),
|
||||
m_ports(ports) {
|
||||
: IntelProcessor(memory),
|
||||
m_interrupt(false),
|
||||
m_ports(ports) {
|
||||
bc.word = de.word = hl.word = 0;
|
||||
installInstructions();
|
||||
}
|
||||
@ -61,8 +59,7 @@ void EightBit::Intel8080::installInstructions() {
|
||||
|
||||
void EightBit::Intel8080::initialise() {
|
||||
Processor::initialise();
|
||||
bc.word = de.word = hl.word = 0;
|
||||
a = f = 0;
|
||||
AF().word = BC().word = DE().word = HL().word = 0;
|
||||
}
|
||||
|
||||
int EightBit::Intel8080::step() {
|
||||
|
||||
@ -148,7 +148,6 @@
|
||||
<ClInclude Include="..\inc\Intel8080.h" />
|
||||
<ClInclude Include="..\inc\PortEventArgs.h" />
|
||||
<ClInclude Include="..\inc\Profiler.h" />
|
||||
<ClInclude Include="..\inc\StatusFlags.h" />
|
||||
<ClInclude Include="stdafx.h" />
|
||||
</ItemGroup>
|
||||
<ItemGroup>
|
||||
|
||||
@ -29,9 +29,6 @@
|
||||
<ClInclude Include="..\inc\Profiler.h">
|
||||
<Filter>Header Files</Filter>
|
||||
</ClInclude>
|
||||
<ClInclude Include="..\inc\StatusFlags.h">
|
||||
<Filter>Header Files</Filter>
|
||||
</ClInclude>
|
||||
</ItemGroup>
|
||||
<ItemGroup>
|
||||
<ClCompile Include="stdafx.cpp">
|
||||
|
||||
Loading…
Reference in New Issue
Block a user