EightBit/M6502/inc/StatusFlags.h
Adrian.Conlon 105032f08a Dump of all my C++ emulators, only Intel8080 integrated so far...
Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
2017-06-04 21:38:34 +01:00

83 lines
1.7 KiB
C++

#pragma once
#include <string>
#include <cstdint>
struct StatusFlags {
bool negative;
bool overflow;
bool reserved;
bool brk;
bool decimal;
bool interrupt;
bool zero;
bool carry;
enum StatusBits {
Negative = 0x80, // N
Overflow = 0x40, // V
Reserved = 0x20, // ignored
Break = 0x10, // B
Decimal = 0x08, // D (use BCD for arithmetic)
Interrupt = 0x04, // I (IRQ disable)
Zero = 0x02, // Z
Carry = 0x01, // C
};
StatusFlags(uint8_t value) {
negative = (value & StatusBits::Negative) != 0;
overflow = (value & StatusBits::Overflow) != 0;
reserved = (value & StatusBits::Reserved) != 0;
brk = (value & StatusBits::Break) != 0;
decimal = (value & StatusBits::Decimal) != 0;
interrupt = (value & StatusBits::Interrupt) != 0;
zero = (value & StatusBits::Zero) != 0;
carry = (value & StatusBits::Carry) != 0;
}
operator uint8_t() const {
uint8_t flags = 0;
if (negative)
flags |= StatusBits::Negative;
if (overflow)
flags |= StatusBits::Overflow;
if (reserved)
flags |= StatusBits::Reserved;
if (brk)
flags |= StatusBits::Break;
if (decimal)
flags |= StatusBits::Decimal;
if (interrupt)
flags |= StatusBits::Interrupt;
if (zero)
flags |= StatusBits::Zero;
if (carry)
flags |= StatusBits::Carry;
return flags;
}
operator std::string() const {
std::string returned;
returned += negative ? "N" : "-";
returned += overflow ? "O" : "-";
returned += reserved ? "R" : "-";
returned += brk ? "B" : "-";
returned += decimal ? "D" : "-";
returned += interrupt ? "I" : "-";
returned += zero ? "Z" : "-";
returned += carry ? "C" : "-";
return returned;
}
};