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Collapse all flags accesses behind setters and getters.

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This commit is contained in:
Thomas Harte 2023-10-11 12:35:17 -04:00
parent 033ba75376
commit 7159366360
3 changed files with 170 additions and 142 deletions
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106
InstructionSets/x86/Implementation/PerformImplementation.hpp
View File

@ -175,12 +175,12 @@ inline void aaa(CPU::RegisterPair16 &ax, Status &status) { // P. 313
The AF and CF flags are set to 1 if the adjustment results in a decimal carry;
otherwise they are cleared to 0. The OF, SF, ZF, and PF flags are undefined.
*/
if((ax.halves.low & 0x0f) > 9 || status.auxiliary_carry) {
if((ax.halves.low & 0x0f) > 9 || status.flag<Flag::AuxiliaryCarry>()) {
ax.halves.low += 6;
++ax.halves.high;
status.auxiliary_carry = status.carry = 1;
status.set_from<Flag::Carry, Flag::AuxiliaryCarry>(1);
} else {
status.auxiliary_carry = status.carry = 0;
status.set_from<Flag::Carry, Flag::AuxiliaryCarry>(0);
}
ax.halves.low &= 0x0f;
}
@ -243,12 +243,12 @@ inline void aas(CPU::RegisterPair16 &ax, Status &status) {
The AF and CF flags are set to 1 if there is a decimal borrow;
otherwise, they are cleared to 0. The OF, SF, ZF, and PF flags are undefined.
*/
if((ax.halves.low & 0x0f) > 9 || status.auxiliary_carry) {
if((ax.halves.low & 0x0f) > 9 || status.flag<Flag::AuxiliaryCarry>()) {
ax.halves.low -= 6;
--ax.halves.high;
status.auxiliary_carry = status.carry = 1;
status.set_from<Flag::Carry, Flag::AuxiliaryCarry>(1);
} else {
status.auxiliary_carry = status.carry = 0;
status.set_from<Flag::Carry, Flag::AuxiliaryCarry>(0);
}
ax.halves.low &= 0x0f;
}
@ -283,22 +283,22 @@ inline void daa(uint8_t &al, Status &status) {
The SF, ZF, and PF flags are set according to the result. The OF flag is undefined.
*/
const uint8_t old_al = al;
const auto old_carry = status.carry;
status.carry = 0;
const auto old_carry = status.flag<Flag::Carry>();
status.set_from<Flag::Carry>(0);
if((al & 0x0f) > 0x09 || status.auxiliary_carry) {
status.carry = old_carry | (al > 0xf9);
if((al & 0x0f) > 0x09 || status.flag<Flag::AuxiliaryCarry>()) {
status.set_from<Flag::Carry>(old_carry | (al > 0xf9));
al += 0x06;
status.auxiliary_carry = 1;
status.set_from<Flag::AuxiliaryCarry>(1);
} else {
status.auxiliary_carry = 0;
status.set_from<Flag::AuxiliaryCarry>(0);
}
if(old_al > 0x99 || old_carry) {
al += 0x60;
status.carry = 1;
status.set_from<Flag::Carry>(1);
} else {
status.carry = 0;
status.set_from<Flag::Carry>(0);
}
status.set_from<uint8_t, Flag::Zero, Flag::Sign, Flag::ParityOdd>(al);
@ -334,22 +334,22 @@ inline void das(uint8_t &al, Status &status) {
The SF, ZF, and PF flags are set according to the result. The OF flag is undefined.
*/
const uint8_t old_al = al;
const auto old_carry = status.carry;
status.carry = 0;
const auto old_carry = status.flag<Flag::Carry>();
status.set_from<Flag::Carry>(0);
if((al & 0x0f) > 0x09 || status.auxiliary_carry) {
status.carry = old_carry | (al < 0x06);
if((al & 0x0f) > 0x09 || status.flag<Flag::AuxiliaryCarry>()) {
status.set_from<Flag::Carry>(old_carry | (al < 0x06));
al -= 0x06;
status.auxiliary_carry = 1;
status.set_from<Flag::AuxiliaryCarry>(1);
} else {
status.auxiliary_carry = 0;
status.set_from<Flag::AuxiliaryCarry>(0);
}
if(old_al > 0x99 || old_carry) {
al -= 0x60;
status.carry = 1;
status.set_from<Flag::Carry>(1);
} else {
status.carry = 0;
status.set_from<Flag::Carry>(0);
}
status.set_from<uint8_t, Flag::Zero, Flag::Sign, Flag::ParityOdd>(al);
@ -365,9 +365,12 @@ void add(IntT &destination, IntT source, Status &status) {
*/
const IntT result = destination + source + (with_carry ? status.carry_bit<IntT>() : 0);
status.carry = Numeric::carried_out<true, Numeric::bit_size<IntT>() - 1>(destination, source, result);
status.auxiliary_carry = Numeric::carried_in<4>(destination, source, result);
status.overflow = Numeric::overflow<true, IntT>(destination, source, result);
status.set_from<Flag::Carry>(
Numeric::carried_out<true, Numeric::bit_size<IntT>() - 1>(destination, source, result));
status.set_from<Flag::AuxiliaryCarry>(
Numeric::carried_in<4>(destination, source, result));
status.set_from<Flag::Overflow>(
Numeric::overflow<true, IntT>(destination, source, result));
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(result);
@ -384,9 +387,12 @@ void sub(IntT &destination, IntT source, Status &status) {
*/
const IntT result = destination - source - (with_borrow ? status.carry_bit<IntT>() : 0);
status.carry = Numeric::carried_out<false, Numeric::bit_size<IntT>() - 1>(destination, source, result);
status.auxiliary_carry = Numeric::carried_in<4>(destination, source, result);
status.overflow = Numeric::overflow<false, IntT>(destination, source, result);
status.set_from<Flag::Carry>(
Numeric::carried_out<false, Numeric::bit_size<IntT>() - 1>(destination, source, result));
status.set_from<Flag::AuxiliaryCarry>(
Numeric::carried_in<4>(destination, source, result));
status.set_from<Flag::Overflow>(
Numeric::overflow<false, IntT>(destination, source, result));
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(result);
@ -415,7 +421,7 @@ void test(IntT &destination, IntT source, Status &status) {
*/
const IntT result = destination & source;
status.carry = status.overflow = 0;
status.set_from<Flag::Carry, Flag::Overflow>(0);
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(result);
}
@ -448,7 +454,7 @@ void mul(IntT &destination_high, IntT &destination_low, IntT source, Status &sta
*/
destination_high = (destination_low * source) >> (8 * sizeof(IntT));
destination_low *= source;
status.overflow = status.carry = destination_high;
status.set_from<Flag::Overflow, Flag::Carry>(destination_high);
}
template <typename IntT>
@ -483,7 +489,7 @@ void imul(IntT &destination_high, IntT &destination_low, IntT source, Status &st
destination_low = IntT(sIntT(destination_low) * sIntT(source));
const auto sign_extension = (destination_low & Numeric::top_bit<IntT>()) ? IntT(~0) : 0;
status.overflow = status.carry = destination_high != sign_extension;
status.set_from<Flag::Overflow, Flag::Carry>(destination_high != sign_extension);
}
template <typename IntT, typename FlowControllerT>
@ -610,8 +616,8 @@ void inc(IntT &destination, Status &status) {
*/
++destination;
status.overflow = destination == Numeric::top_bit<IntT>();
status.auxiliary_carry = ((destination - 1) ^ destination) & 0x10;
status.set_from<Flag::Overflow>(destination == Numeric::top_bit<IntT>());
status.set_from<Flag::AuxiliaryCarry>(((destination - 1) ^ destination) & 0x10);
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
}
@ -643,12 +649,12 @@ void dec(IntT &destination, Status &status) {
The CF flag is not affected.
The OF, SF, ZF, AF, and PF flags are set according to the result.
*/
status.overflow = destination == Numeric::top_bit<IntT>();
status.set_from<Flag::Overflow>(destination == Numeric::top_bit<IntT>());
--destination;
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
status.auxiliary_carry = ((destination + 1) ^ destination) & 0x10;
status.set_from<Flag::AuxiliaryCarry>(((destination + 1) ^ destination) & 0x10);
}
template <typename IntT>
@ -662,8 +668,7 @@ void and_(IntT &destination, IntT source, Status &status) {
*/
destination &= source;
status.overflow = 0;
status.carry = 0;
status.set_from<Flag::Overflow, Flag::Carry>(0);
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
}
@ -678,8 +683,7 @@ void or_(IntT &destination, IntT source, Status &status) {
*/
destination |= source;
status.overflow = 0;
status.carry = 0;
status.set_from<Flag::Overflow, Flag::Carry>(0);
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
}
@ -694,8 +698,7 @@ void xor_(IntT &destination, IntT source, Status &status) {
*/
destination ^= source;
status.overflow = 0;
status.carry = 0;
status.set_from<Flag::Overflow, Flag::Carry>(0);
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
}
@ -712,12 +715,12 @@ void neg(IntT &destination, Status &status) {
The CF flag cleared to 0 if the source operand is 0; otherwise it is set to 1.
The OF, SF, ZF, AF, and PF flags are set according to the result.
*/
status.auxiliary_carry = Numeric::carried_in<4>(IntT(0), destination, IntT(-destination));
status.set_from<Flag::AuxiliaryCarry>(Numeric::carried_in<4>(IntT(0), destination, IntT(-destination)));
destination = -destination;
status.carry = destination;
status.overflow = destination == Numeric::top_bit<IntT>();
status.set_from<Flag::Carry>(destination);
status.set_from<Flag::Overflow>(destination == Numeric::top_bit<IntT>());
status.set_from<IntT, Flag::Zero, Flag::Sign, Flag::ParityOdd>(destination);
}
@ -791,13 +794,14 @@ void cwd(IntT &dx, IntT ax) {
dx = ax & Numeric::top_bit<IntT>() ? IntT(~0) : IntT(0);
}
inline void clc(Status &status) { status.carry = 0; }
inline void cld(Status &status) { status.direction = 0; }
inline void cli(Status &status) { status.interrupt = 0; } // TODO: quite a bit more in protected mode.
inline void stc(Status &status) { status.carry = 1; }
inline void std(Status &status) { status.direction = 1; }
inline void sti(Status &status) { status.interrupt = 1; } // TODO: quite a bit more in protected mode.
inline void cmc(Status &status) { status.carry = !status.carry; }
// TODO: changes to the interrupt flag do quite a lot more in protected mode.
inline void clc(Status &status) { status.set_from<Flag::Carry>(0); }
inline void cld(Status &status) { status.set_from<Flag::Direction>(0); }
inline void cli(Status &status) { status.set_from<Flag::Interrupt>(0); }
inline void stc(Status &status) { status.set_from<Flag::Carry>(1); }
inline void std(Status &status) { status.set_from<Flag::Direction>(1); }
inline void sti(Status &status) { status.set_from<Flag::Interrupt>(1); }
inline void cmc(Status &status) { status.set_from<Flag::Carry>(!status.flag<Flag::Carry>()); }
}

54
InstructionSets/x86/Status.hpp
View File

@ -77,21 +77,9 @@ enum class Condition {
LessOrEqual
};
struct Status {
// Non-zero => set; zero => unset.
uint32_t carry;
uint32_t auxiliary_carry;
uint32_t sign;
uint32_t overflow;
uint32_t trap;
uint32_t interrupt;
uint32_t direction;
// Zero => set; non-zero => unset.
uint32_t zero;
// Odd number of bits => set; even => unset.
uint32_t parity;
class Status {
public:
using FlagT = uint32_t;
// Flag getters.
template <Flag flag> bool flag() {
@ -123,6 +111,17 @@ struct Status {
}
// Convenience setters.
/// Sets all of @c flags as a function of @c value:
/// • Flag::Zero: sets the zero flag if @c value is zero;
/// • Flag::Sign: sets the sign flag if the top bit of @c value is one;
/// • Flag::ParityOdd: sets parity based on the low 8 bits of @c value;
/// • Flag::Carry: sets carry if @c value is non-zero;
/// • Flag::AuxiliaryCarry: sets auxiliary carry if @c value is non-zero;
/// • Flag::Overflow: sets overflow if @c value is non-zero;
/// • Flag::Interrupt: sets interrupt if @c value is non-zero;
/// • Flag::Trap: sets interrupt if @c value is non-zero;
/// • Flag::Direction: sets direction if @c value is non-zero.
template <typename IntT, Flag... flags> void set_from(IntT value) {
for(const auto flag: {flags...}) {
switch(flag) {
@ -130,9 +129,18 @@ struct Status {
case Flag::Zero: zero = value; break;
case Flag::Sign: sign = value & Numeric::top_bit<IntT>(); break;
case Flag::ParityOdd: parity = value; break;
case Flag::Carry: carry = value; break;
case Flag::AuxiliaryCarry: auxiliary_carry = value; break;
case Flag::Overflow: overflow = value; break;
case Flag::Interrupt: interrupt = value; break;
case Flag::Trap: trap = value; break;
case Flag::Direction: direction = value; break;
}
}
}
template <Flag... flags> void set_from(FlagT value) {
set_from<FlagT, flags...>(value);
}
template <typename IntT> IntT carry_bit() const { return carry ? 1 : 0; }
bool not_parity_bit() const {
@ -179,6 +187,22 @@ struct Status {
bool operator ==(const Status &rhs) const {
return get() == rhs.get();
}
private:
// Non-zero => set; zero => unset.
uint32_t carry;
uint32_t auxiliary_carry;
uint32_t sign;
uint32_t overflow;
uint32_t trap;
uint32_t interrupt;
uint32_t direction;
// Zero => set; non-zero => unset.
uint32_t zero;
// Odd number of bits => set; even => unset.
uint32_t parity;
};
}

4
OSBindings/Mac/Clock SignalTests/8088Tests.mm
View File

@ -197,8 +197,8 @@ class FlowController {
push(status_.get(), true);
status_.interrupt = 0;
status_.trap = 0;
using Flag = InstructionSet::x86::Flag;
status_.set_from<Flag::Interrupt, Flag::Trap>(0);
// Push CS and IP.
push(registers_.cs_);