Created
March 24, 2017 09:01
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| typedef struct { | |
| char *address; | |
| char *reference; | |
| } label_t; | |
| void emit_label_reference(label_t *label) { | |
| if (label->address) { | |
| emit4(label->address - emit_pointer); | |
| } else { | |
| char *reference = emit_pointer; | |
| emit4(label->reference - emit_pointer); | |
| label->reference = reference; | |
| } | |
| } | |
| void resolve_label(label_t *label) { | |
| char *address = emit_pointer; | |
| label->address = address; | |
| char *reference = label->reference; | |
| while (reference) { | |
| int32_t offset = *(int32_t *)reference; | |
| *(int32_t *)reference = address - reference; | |
| reference += offset; | |
| } | |
| label->reference = NULL; | |
| } | |
| // ... | |
| if (token == TOKEN_IF) { | |
| next_token(); | |
| label_t end = {0}; | |
| expr(); | |
| emit(BRZ); | |
| label_t next = {0}; | |
| emit_label_reference(&next); | |
| stmt_block(); | |
| while (token == TOKEN_ELSEIF) { | |
| next_token(); | |
| emit(JMP); | |
| emit_label_reference(&end); | |
| resolve_label(&next); | |
| expr(); | |
| emit(BRZ); | |
| next.address = NULL; | |
| emit_label_reference(&next); | |
| stmt_block(); | |
| } | |
| if (token == TOKEN_ELSE) { | |
| next_token(); | |
| emit(JMP); | |
| emit_label_reference(&end); | |
| resolve_label(&next); | |
| stmt_block(); | |
| } | |
| resolve_label(&end); |
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