Implement compiling `if`, but we need relative addressing first.
Chris Pressey
9 years ago
| 6 | 6 | ) |
| 7 | 7 | from sixtypical.emitter import Label, Byte |
| 8 | 8 | from sixtypical.gen6502 import ( |
| 9 | Immediate, Absolute, | |
| 9 | Immediate, Absolute, Relative, | |
| 10 | 10 | LDA, LDX, LDY, STA, STX, STY, |
| 11 | 11 | CLC, SEC, ADC, SBC, ROL, ROR, |
| 12 | RTS, JSR, | |
| 13 | 12 | INC, INX, INY, DEC, DEX, DEY, |
| 14 | 13 | CMP, CPX, CPY, AND, ORA, EOR, |
| 14 | BCC, BNE, | |
| 15 | JMP, JSR, RTS, | |
| 15 | 16 | ) |
| 16 | 17 | |
| 17 | 18 | |
| 57 | 58 | |
| 58 | 59 | def compile_block(self, block): |
| 59 | 60 | assert isinstance(block, Block) |
| 60 | label = self.emitter.make_label() | |
| 61 | 61 | for instr in block.instrs: |
| 62 | 62 | self.compile_instr(instr) |
| 63 | return label | |
| 64 | 63 | |
| 65 | 64 | def compile_instr(self, instr): |
| 66 | 65 | assert isinstance(instr, Instr) |
| 167 | 166 | label = self.labels[instr.name] |
| 168 | 167 | self.emitter.emit(JSR(Absolute(label))) |
| 169 | 168 | elif opcode == 'if': |
| 170 | raise NotImplementedError | |
| 169 | cls = { | |
| 170 | 'c': BCC, | |
| 171 | 'z': BNE, | |
| 172 | }.get(src.name) | |
| 173 | if cls is None: | |
| 174 | raise UnsupportedOpcodeError(instr) | |
| 175 | else_label = Label('else_label') | |
| 176 | self.emitter.emit(cls(Relative(else_label))) | |
| 177 | self.compile_block(instr.block1) | |
| 178 | if instr.block2: | |
| 179 | end_label = Label('end_label') | |
| 180 | self.emitter.emit(JMP(Absolute(end_label))) | |
| 181 | self.emitter.resolve_label(else_label) | |
| 182 | self.compile_block(instr.block2) | |
| 183 | self.emitter.resolve_label(end_label) | |
| 184 | else: | |
| 185 | self.emitter.resolve_label(else_label) | |
| 171 | 186 | else: |
| 172 | 187 | raise NotImplementedError |
| 6 | 6 | def size(self): |
| 7 | 7 | """Size of the operand for the mode (not including the opcode)""" |
| 8 | 8 | raise NotImplementedError |
| 9 | ||
| 10 | def __repr__(self): | |
| 11 | return "%s(%r)" % (self.__class__.__name__, self.value) | |
| 9 | 12 | |
| 10 | 13 | |
| 11 | 14 | class Implied(AddressingMode): |
| 30 | 33 | def serialize(self): |
| 31 | 34 | return self.value.serialize() |
| 32 | 35 | |
| 33 | def __repr__(self): | |
| 34 | return "%s(%r)" % (self.__class__.__name__, self.value) | |
| 35 | ||
| 36 | 36 | |
| 37 | 37 | class Absolute(AddressingMode): |
| 38 | 38 | def __init__(self, value): |
| 45 | 45 | def serialize(self): |
| 46 | 46 | return self.value.serialize() |
| 47 | 47 | |
| 48 | def __repr__(self): | |
| 49 | return "%s(%r)" % (self.__class__.__name__, self.value) | |
| 48 | ||
| 49 | class Relative(AddressingMode): | |
| 50 | def __init__(self, value): | |
| 51 | assert isinstance(value, (Byte, Label)) | |
| 52 | self.value = value | |
| 53 | ||
| 54 | def size(self): | |
| 55 | return 1 | |
| 56 | ||
| 57 | def serialize(self): | |
| 58 | # HA | |
| 59 | return chr(0xff) | |
| 50 | 60 | |
| 51 | 61 | |
| 52 | 62 | class Opcode(Emittable): |
| 80 | 90 | } |
| 81 | 91 | |
| 82 | 92 | |
| 93 | class BCC(Opcode): | |
| 94 | opcodes = { | |
| 95 | Relative: 0x90, | |
| 96 | } | |
| 97 | ||
| 98 | ||
| 99 | class BNE(Opcode): | |
| 100 | opcodes = { | |
| 101 | Relative: 0xd0, | |
| 102 | } | |
| 103 | ||
| 104 | ||
| 83 | 105 | class CLC(Opcode): |
| 84 | 106 | opcodes = { |
| 85 | 107 | Implied: 0x18 |
| 150 | 172 | } |
| 151 | 173 | |
| 152 | 174 | |
| 175 | class JMP(Opcode): | |
| 176 | opcodes = { | |
| 177 | Absolute: 0x4c, | |
| 178 | } | |
| 179 | ||
| 180 | ||
| 153 | 181 | class JSR(Opcode): |
| 154 | 182 | opcodes = { |
| 155 | 183 | Absolute: 0x20, |
| 117 | 117 | | shr a |
| 118 | 118 | | } |
| 119 | 119 | = 00c0a900a200a0008d46c08e46c08c46c0381869016d46c0e901ed46c0ee46c0e8c8ce46c0ca8829ff2d46c009ff0d46c049ff4d46c0c901cd46c0e001ec46c0c001cc46c02a6a60 |
| 120 | ||
| 121 | Compiling `if`. | |
| 122 | ||
| 123 | | routine main | |
| 124 | | trashes a, x, y, z, n, c, v | |
| 125 | | { | |
| 126 | | ld a, 0 | |
| 127 | | if z { | |
| 128 | | ld y, 1 | |
| 129 | | } else { | |
| 130 | | ld y, 2 | |
| 131 | | } | |
| 132 | | } | |
| 133 | = 00c0 |