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Fill in line decoders for 5, 6 and 7.

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This leaves 9, D and E to go.
This commit is contained in:
Thomas Harte 2022-04-12 08:44:32 -04:00
parent 17e761d6c6
commit bca18e7aba
1 changed files with 26 additions and 5 deletions
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31
InstructionSets/68k/Decoder.cpp
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@ -131,6 +131,8 @@ template <Operation operation> Preinstruction Predecoder::decode(uint16_t instru
// TODO: be careful that decoders for ADD, SUB, etc, must check the instruction a little // TODO: be careful that decoders for ADD, SUB, etc, must check the instruction a little
// further to determine whether they're ADDI, SUBI, etc or the regular versions. // further to determine whether they're ADDI, SUBI, etc or the regular versions.
// TODO: be willing to mutate Scc into DBcc.
} }
// MARK: - Page decoders. // MARK: - Page decoders.
@ -325,18 +327,37 @@ Preinstruction Predecoder::decode4(uint16_t instruction) {
} }
Preinstruction Predecoder::decode5(uint16_t instruction) { Preinstruction Predecoder::decode5(uint16_t instruction) {
(void)instruction; switch(instruction & 0x1c0) {
// 4-11 (p115)
case 0x000: return decode<Operation::ADDQb>(instruction);
case 0x040: return decode<Operation::ADDQw>(instruction);
case 0x080: return decode<Operation::ADDQl>(instruction);
// 4-181 (p285)
case 0x100: return decode<Operation::SUBQb>(instruction);
case 0x140: return decode<Operation::SUBQw>(instruction);
case 0x180: return decode<Operation::SUBQl>(instruction);
default: break;
}
switch(instruction & 0x0c0) {
// 4-173 (p276), though this'll also hit DBcc 4-91 (p195)
case 0x0c0: return decode<Operation::Scc>(instruction);
default: break;
}
return Preinstruction(); return Preinstruction();
} }
Preinstruction Predecoder::decode6(uint16_t instruction) { Preinstruction Predecoder::decode6(uint16_t instruction) {
(void)instruction; // 4-25 (p129), 4-59 (p163) and 4-55 (p159)
return Preinstruction(); return decode<Operation::Bcc>(instruction);
} }
Preinstruction Predecoder::decode7(uint16_t instruction) { Preinstruction Predecoder::decode7(uint16_t instruction) {
(void)instruction; // 4-134 (p238)
return Preinstruction(); return decode<Operation::MOVEq>(instruction);
} }
Preinstruction Predecoder::decode8(uint16_t instruction) { Preinstruction Predecoder::decode8(uint16_t instruction) {