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Add various SUB/SBC instructions to the 6809 processor

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2018-08-24 00:14:44 +01:00
parent 595a9a0af7
commit c7ca555995
2 changed files with 41 additions and 24 deletions
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3
MC6809/inc/mc6809.h
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@ -290,6 +290,9 @@ namespace EightBit {
uint8_t ror(uint8_t operand);
void rti();
void rts();
uint8_t sbc(uint8_t operand, uint8_t data);
uint8_t sub(uint8_t operand, uint8_t data, int carry = 0);
register16_t sub(register16_t operand, register16_t data);
uint8_t sex(uint8_t from);
void swi();
void swi2();

62
MC6809/src/mc6809.cpp
View File

@ -303,16 +303,16 @@ int EightBit::mc6809::executeUnprefixed(uint8_t opcode) {
// SBC
// SBCA
case 0x82: addCycles(4); break; // SBC (SBCA immediate)
case 0x92: addCycles(4); break; // SBC (SBCA direct)
case 0xa2: addCycles(4); break; // SBC (SBCA indexed)
case 0xb2: addCycles(5); break; // SBC (SBCB extended)
case 0x82: addCycles(4); A() = sbc(A(), AM_immediate_byte()); break; // SBC (SBCA immediate)
case 0x92: addCycles(4); A() = sbc(A(), AM_direct_byte()); break; // SBC (SBCA direct)
case 0xa2: addCycles(4); A() = sbc(A(), AM_indexed_byte()); break; // SBC (SBCA indexed)
case 0xb2: addCycles(5); A() = sbc(A(), AM_extended_byte()); break; // SBC (SBCB extended)
// SBCB
case 0xc2: addCycles(4); break; // SBC (SBCB immediate)
case 0xd2: addCycles(4); break; // SBC (SBCB direct)
case 0xe2: addCycles(4); break; // SBC (SBCB indexed)
case 0xf2: addCycles(5); break; // SBC (SBCB extended)
case 0xc2: addCycles(4); B() = sbc(B(), AM_immediate_byte()); break; // SBC (SBCB immediate)
case 0xd2: addCycles(4); B() = sbc(B(), AM_direct_byte()); break; // SBC (SBCB direct)
case 0xe2: addCycles(4); B() = sbc(B(), AM_indexed_byte()); break; // SBC (SBCB indexed)
case 0xf2: addCycles(5); B() = sbc(B(), AM_extended_byte()); break; // SBC (SBCB extended)
// SEX
case 0x1d: addCycles(2); A() = sex(B()); break; // SEX (inherent)
@ -347,22 +347,22 @@ int EightBit::mc6809::executeUnprefixed(uint8_t opcode) {
// SUB
// SUBA
case 0x80: addCycles(2); break; // SUB (SUBA immediate)
case 0x90: addCycles(4); break; // SUB (SUBA direct)
case 0xa0: addCycles(4); break; // SUB (SUBA indexed)
case 0xb0: addCycles(5); break; // SUB (SUBA extended)
case 0x80: addCycles(2); A() = sub(A(), AM_immediate_byte()); break; // SUB (SUBA immediate)
case 0x90: addCycles(4); A() = sub(A(), AM_direct_byte()); break; // SUB (SUBA direct)
case 0xa0: addCycles(4); A() = sub(A(), AM_indexed_byte()); break; // SUB (SUBA indexed)
case 0xb0: addCycles(5); A() = sub(A(), AM_extended_byte()); break; // SUB (SUBA extended)
// SUBB
case 0xc0: addCycles(2); break; // SUB (SUBB immediate)
case 0xd0: addCycles(4); break; // SUB (SUBB direct)
case 0xe0: addCycles(4); break; // SUB (SUBB indexed)
case 0xf0: addCycles(5); break; // SUB (SUBB extended)
case 0xc0: addCycles(2); B() = sub(B(), AM_immediate_byte()); break; // SUB (SUBB immediate)
case 0xd0: addCycles(4); B() = sub(B(), AM_direct_byte()); break; // SUB (SUBB direct)
case 0xe0: addCycles(4); B() = sub(B(), AM_indexed_byte()); break; // SUB (SUBB indexed)
case 0xf0: addCycles(5); B() = sub(B(), AM_extended_byte()); break; // SUB (SUBB extended)
// SUBD
case 0x83: addCycles(4); break; // SUB (SUBD immediate)
case 0x93: addCycles(6); break; // SUB (SUBD direct)
case 0xa3: addCycles(6); break; // SUB (SUBD indexed)
case 0xb3: addCycles(7); break; // SUB (SUBD extended)
case 0x83: addCycles(4); D() = sub(D(), AM_immediate_word()); break; // SUB (SUBD immediate)
case 0x93: addCycles(6); D() = sub(D(), AM_direct_word()); break; // SUB (SUBD direct)
case 0xa3: addCycles(6); D() = sub(D(), AM_indexed_word()); break; // SUB (SUBD indexed)
case 0xb3: addCycles(7); D() = sub(D(), AM_extended_word()); break; // SUB (SUBD extended)
// SWI
case 0x3f: addCycles(19); swi(); break; // SWI (inherent)
@ -742,13 +742,11 @@ uint8_t EightBit::mc6809::clr() {
}
void EightBit::mc6809::cmp(const uint8_t operand, const uint8_t data) {
const register16_t difference = operand - data;
adjustSubtraction(operand, data, difference);
sub(operand, data);
}
void EightBit::mc6809::cmp(register16_t operand, register16_t data) {
const uint32_t difference = operand.word - data.word;
adjustSubtraction(operand, data, difference);
sub(operand, data);
}
uint8_t EightBit::mc6809::com(uint8_t operand) {
@ -1113,3 +1111,19 @@ EightBit::register16_t EightBit::mc6809::st(register16_t data) {
adjustNZ(data);
return data;
}
uint8_t EightBit::mc6809::sbc(uint8_t operand, uint8_t data) {
return sub(operand, data, CC() & CF);
}
uint8_t EightBit::mc6809::sub(uint8_t operand, uint8_t data, int carry) {
const register16_t subtraction = operand - data - carry;
adjustSubtraction(operand, data, subtraction);
return subtraction.low;
}
EightBit::register16_t EightBit::mc6809::sub(register16_t operand, register16_t data) {
const uint32_t subtraction = operand.word - data.word;
adjustSubtraction(operand, data, subtraction);
return subtraction & Mask16;
}