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changeset 55:8e32696380f3
added expression evaluation and checking function
| author | lost |
|---|---|
| date | Sun, 04 Jan 2009 21:42:54 +0000 |
| parents | 360d53062bb9 |
| children | 55260a178667 |
| files | src/lwasm.c src/lwasm.h |
| diffstat | 2 files changed, 56 insertions(+), 1 deletions(-) [+] |
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--- a/src/lwasm.c Sun Jan 04 20:38:12 2009 +0000 +++ b/src/lwasm.c Sun Jan 04 21:42:54 2009 +0000 @@ -1,6 +1,6 @@ /* lwasm.c -Copyright © 2008 William Astle +Copyright © 2009 William Astle This file is part of LWASM. @@ -195,6 +195,52 @@ return(lwasm_expr_eval(inp, outp, lwasm_expr_lookup_symbol, &st)); } +int lwasm_expr_result(asmstate_t *as, lwasm_line_t *l, char **inp, int flag, int *val) +{ + lwasm_expr_stack_t *s; + char *ep; + int rval; + + s = lwasm_evaluate_expr(as, l, *inp, &ep); + if (!s) + { + register_error(as, l, 1, "Bad expression"); + *val = 0; + return -1; + } + *inp = ep; + + if (flag & EXPR_PASS1CONST && as -> passnum == 1 && !lwasm_expr_is_constant(s)) + { + register_error(as, l, 1, "Illegal incomplete reference (pass 1)"); + *val = 0; + lwasm_expr_stack_free(s); + return -1; + } + if (flag & EXPR_PASS2CONST && as -> passnum == 2 && !lwasm_expr_is_constant(s)) + { + register_error(as, l, 2, "Incomplete reference (pass 2)"); + *val = 0; + lwasm_expr_stack_free(s); + return -1; + } + *val = lwasm_expr_get_value(s); + lwasm_expr_stack_free(s); + + if (flag & EXPR_BYTE && as -> passnum == 2 && (*val < -128 || *val > 255)) + { + register_error(as, l, 2, "Byte overflow"); + *val &= 0xff; + return -1; + } + if (flag & EXPR_BYTE) + { + *val &= 0xff; + } + + return 0; +} + void debug_message(int level, const char *fmt, ...) { va_list args;
--- a/src/lwasm.h Sun Jan 04 20:38:12 2009 +0000 +++ b/src/lwasm.h Sun Jan 04 21:42:54 2009 +0000 @@ -116,6 +116,15 @@ __lwasm_E__ lwasm_expr_stack_t *lwasm_evaluate_expr(asmstate_t *as, lwasm_line_t *l, const char *inp, const char **outp); + +// also throw an error on expression eval failure +// return 0 on ok, -1 on error +#define EXPR_NOFLAG 0 +#define EXPR_PASS1CONST 1 +#define EXPR_PASS2CONST 2 +#define EXPR_BYTE 4 +__lwasm_E__ int lwasm_expr_result(asmstate_t *as, lwasm_line_t *l, char **inp, int flag, int *val); + #undef __lwasm_E__