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Create empty line decoders.

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This commit is contained in:
Thomas Harte 2022-04-12 08:16:29 -04:00
parent dd5bdd67d7
commit c50556dde4
2 changed files with 82 additions and 0 deletions
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70
InstructionSets/68k/Decoder.cpp
View File

@ -132,6 +132,26 @@ template <Operation operation> Preinstruction Predecoder::decode(uint16_t instru
// MARK: - Page decoders.
Preinstruction Predecoder::decode0(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode1(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode2(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode3(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode4(uint16_t instruction) {
switch(instruction & 0xfff) {
case 0xe70: return decode<Operation::RESET>(instruction); // 6-83 (p537)
@ -228,6 +248,21 @@ Preinstruction Predecoder::decode4(uint16_t instruction) {
return Preinstruction();
}
Preinstruction Predecoder::decode5(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode6(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode7(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decode8(uint16_t instruction) {
// 4-171 (p275)
if((instruction & 0x1f0) == 0x100) return decode<Operation::SBCD>(instruction);
@ -249,6 +284,15 @@ Preinstruction Predecoder::decode8(uint16_t instruction) {
return Preinstruction();
}
Preinstruction Predecoder::decode9(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decodeA(uint16_t) {
return Preinstruction();
}
Preinstruction Predecoder::decodeB(uint16_t instruction) {
// 4-100 (p204)
switch(instruction & 0x0c0) {
@ -302,15 +346,41 @@ Preinstruction Predecoder::decodeC(uint16_t instruction) {
return Preinstruction();
}
Preinstruction Predecoder::decodeD(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decodeE(uint16_t instruction) {
(void)instruction;
return Preinstruction();
}
Preinstruction Predecoder::decodeF(uint16_t) {
return Preinstruction();
}
// MARK: - Main decoder.
Preinstruction Predecoder::decode(uint16_t instruction) {
// Divide first based on line.
switch(instruction & 0xf000) {
case 0x0000: return decode0(instruction);
case 0x1000: return decode1(instruction);
case 0x2000: return decode2(instruction);
case 0x3000: return decode3(instruction);
case 0x4000: return decode4(instruction);
case 0x5000: return decode5(instruction);
case 0x6000: return decode6(instruction);
case 0x7000: return decode7(instruction);
case 0x8000: return decode8(instruction);
case 0x9000: return decode9(instruction);
case 0xa000: return decodeA(instruction);
case 0xb000: return decodeB(instruction);
case 0xc000: return decodeC(instruction);
case 0xd000: return decodeD(instruction);
case 0xe000: return decodeE(instruction);
case 0xf000: return decodeF(instruction);
default: break;
}

12
InstructionSets/68k/Decoder.hpp
View File

@ -26,10 +26,22 @@ class Predecoder {
private:
// Page by page decoders; each gets a bit ad hoc so
// it is neater to separate them.
Preinstruction decode0(uint16_t instruction);
Preinstruction decode1(uint16_t instruction);
Preinstruction decode2(uint16_t instruction);
Preinstruction decode3(uint16_t instruction);
Preinstruction decode4(uint16_t instruction);
Preinstruction decode5(uint16_t instruction);
Preinstruction decode6(uint16_t instruction);
Preinstruction decode7(uint16_t instruction);
Preinstruction decode8(uint16_t instruction);
Preinstruction decode9(uint16_t instruction);
Preinstruction decodeA(uint16_t instruction);
Preinstruction decodeB(uint16_t instruction);
Preinstruction decodeC(uint16_t instruction);
Preinstruction decodeD(uint16_t instruction);
Preinstruction decodeE(uint16_t instruction);
Preinstruction decodeF(uint16_t instruction);
// Specific instruction decoders.
template <Operation operation> Preinstruction decode(uint16_t instruction);