6502/6502-cpp
1
0
Fork 0
mirror of https://github.com/lefticus/6502-cpp.git synced 2025-05-16 15:38:15 +00:00
Code Issues Projects Releases Wiki Activity

Implement some more instructions, and fix typos.

Browse Source 
Implement 16-bit shrl (new instruction).

Implement movl with a 16-bit literal value. Add the 6502 ROR instruction.
This commit is contained in:
Marko Mäkelä 2016-10-06 17:41:33 +03:00
parent 88d197e0d7
commit 4ed4e6a94c
1 changed files with 35 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
src/main.cpp
View File

@ -112,6 +112,7 @@ struct mos6502 : ASMLine
php,
plp,
lsr,
ror,
AND,
inc,
dec,
@ -148,6 +149,7 @@ struct mos6502 : ASMLine
case OpCode::php:
case OpCode::plp:
case OpCode::lsr:
case OpCode::ror:
case OpCode::AND:
case OpCode::inc:
case OpCode::dec:
@ -184,6 +186,7 @@ struct mos6502 : ASMLine
case OpCode::php:
case OpCode::plp:
case OpCode::lsr:
case OpCode::ror:
case OpCode::AND:
case OpCode::inc:
case OpCode::dec:
@ -248,6 +251,8 @@ struct mos6502 : ASMLine
return "plp";
case OpCode::lsr:
return "lsr";
case OpCode::ror:
return "ror";
case OpCode::AND:
return "and";
case OpCode::inc:
@ -318,6 +323,7 @@ struct i386 : ASMLine
movzbl,
movzwl,
shrb,
shrl,
xorl,
andl,
andb,
@ -363,6 +369,7 @@ struct i386 : ASMLine
if (o == "movzwl") return OpCode::movzwl;
if (o == "movzbl") return OpCode::movzbl;
if (o == "shrb") return OpCode::shrb;
if (o == "shrl") return OpCode::shrl;
if (o == "xorl") return OpCode::xorl;
if (o == "andl") return OpCode::andl;
if (o == "ret") return OpCode::ret;
@ -475,6 +482,11 @@ void translate_instruction(std::vector<mos6502> &instructions, const i386::OpCod
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num));
instructions.emplace_back(mos6502::OpCode::lda, get_register(o1.reg_num, 1));
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num, 1));
} else if (o1.type == Operand::Type::literal && o2.type == Operand::Type::reg) {
instructions.emplace_back(mos6502::OpCode::lda, Operand(o1.type, "#<" + o1.value));
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num));
instructions.emplace_back(mos6502::OpCode::lda, Operand(o1.type, "#>" + o1.value));
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num, 1));
} else {
throw std::runtime_error("Cannot translate movl instruction");
}
@ -486,7 +498,7 @@ void translate_instruction(std::vector<mos6502> &instructions, const i386::OpCod
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num));
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num, 1));
} else {
throw std::runtime_error("Cannot translate movl instruction");
throw std::runtime_error("Cannot translate xorl instruction");
}
break;
case i386::OpCode::movb:
@ -550,6 +562,25 @@ void translate_instruction(std::vector<mos6502> &instructions, const i386::OpCod
throw std::runtime_error("Cannot translate shrb instruction");
}
break;
case i386::OpCode::shrl:
if (o1.type == Operand::Type::reg || o2.type == Operand::Type::reg) {
const auto do_shift = [&instructions](const int reg_num) {
instructions.emplace_back(mos6502::OpCode::lsr, get_register(reg_num, 1));
instructions.emplace_back(mos6502::OpCode::ror, get_register(reg_num));
};
if (o1.type == Operand::Type::literal) {
const auto count = parse_8bit_literal(o1.value);
for (int i = 0; i < count; ++i) {
do_shift(o2.reg_num);
}
} else {
do_shift(o1.reg_num);
}
} else {
throw std::runtime_error("Cannot translate shrl instruction");
}
break;
case i386::OpCode::testb:
if (o1.type == Operand::Type::reg && o2.type == Operand::Type::reg && o1.reg_num == o2.reg_num) {
// this just tests the register for 0
@ -625,7 +656,7 @@ void translate_instruction(std::vector<mos6502> &instructions, const i386::OpCod
instructions.emplace_back(mos6502::OpCode::lda, get_register(o2.reg_num));
instructions.emplace_back(mos6502::OpCode::cmp, Operand(o1.type, fixup_8bit_literal(o1.value)));
} else {
throw std::runtime_error("Cannot translate cmb instruction");
throw std::runtime_error("Cannot translate cmpb instruction");
}
break;
case i386::OpCode::andb:
@ -684,7 +715,7 @@ void translate_instruction(std::vector<mos6502> &instructions, const i386::OpCod
instructions.emplace_back(mos6502::OpCode::lda, get_register(o1.reg_num, 1));
instructions.emplace_back(mos6502::OpCode::pha);
} else {
throw std::runtime_error("Cannot translate sbb instruction");
throw std::runtime_error("Cannot translate pushl instruction");
}
break;
@ -701,7 +732,7 @@ void translate_instruction(std::vector<mos6502> &instructions, const i386::OpCod
instructions.emplace_back(mos6502::OpCode::eor, Operand(Operand::Type::literal, "#$ff")); // invert the bits
instructions.emplace_back(mos6502::OpCode::sta, get_register(o2.reg_num)); // place the value
} else {
throw std::runtime_error("Cannot translate sbb instruction");
throw std::runtime_error("Cannot translate sbbb instruction");
}
break;