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Implement AND for the 6809

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2018-08-19 14:08:49 +01:00
parent 33fbad7132
commit a125c4c24c
2 changed files with 22 additions and 0 deletions
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1
MC6809/inc/mc6809.h
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@ -110,6 +110,7 @@ namespace EightBit {
uint8_t adc(uint8_t operand, uint8_t data);
uint8_t add(uint8_t operand, uint8_t data, int carry = 0);
register16_t add(register16_t operand, register16_t data);
uint8_t andr(uint8_t operand, uint8_t data);
uint8_t neg(uint8_t operand);
register16_t m_d;

21
MC6809/src/mc6809.cpp
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@ -60,6 +60,19 @@ int EightBit::mc6809::execute(uint8_t cell) {
case 0xe3: addCycles(6); D() = add(D(), AM_indexed_word()); break; // ADD (ADDD, indexed)
case 0xf3: addCycles(7); D() = add(D(), AM_extended_word()); break; // ADD (ADDD, extended)
// AND
case 0x84: addCycles(2); A() = andr(A(), AM_immediate_byte()); break; // AND (ANDA, immediate)
case 0x94: addCycles(4); A() = andr(A(), AM_direct_byte()); break; // AND (ANDA, direct)
case 0xa4: addCycles(4); A() = andr(A(), AM_indexed_byte()); break; // AND (ANDA, indexed)
case 0xb4: addCycles(5); A() = andr(A(), AM_extended_byte()); break; // AND (ANDA, extended)
case 0xc4: addCycles(2); B() = andr(B(), AM_immediate_byte()); break; // AND (ANDB, immediate)
case 0xd4: addCycles(4); B() = andr(B(), AM_direct_byte()); break; // AND (ANDB, direct)
case 0xe4: addCycles(4); B() = andr(B(), AM_indexed_byte()); break; // AND (ANDB, indexed)
case 0xf4: addCycles(5); B() = andr(B(), AM_extended_byte()); break; // AND (ANDB, extended)
case 0x1c: addCycles(3); CC() = andr(CC(), AM_immediate_byte()); break; // AND (ANDCC, immediate)
// NEG
case 0x00: addCycles(6); BUS().write(neg(AM_direct_byte())); break; // NEG (direct)
case 0x40: addCycles(2); A() = neg(A()); break; // NEG (NEGA, inherent)
@ -252,3 +265,11 @@ EightBit::register16_t EightBit::mc6809::add(register16_t operand, register16_t
setFlag(CC(), CF, addition & Bit16);
return result;
}
uint8_t EightBit::mc6809::andr(uint8_t operand, uint8_t data) {
const auto result = operand & data;
clearFlag(CC(), VF);
setFlag(CC(), NF, result & Bit7);
setFlag(CC(), ZF, result == 0);
return result;
}