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comparison src/error.s @ 75:5f8f0b0781e8
Split some code into separate files for easier management (3)
Because the source for lwbasic is so large, split it into several
different files to make it easier to navigate and modify. This is
part three of the split. Includes a file missing from part one.
| author | William Astle <lost@l-w.ca> |
|---|---|
| date | Sun, 06 Aug 2023 00:41:26 -0600 |
| parents | |
| children | bb50ac9fdf37 |
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| 74:e74d00ac6b79 | 75:5f8f0b0781e8 |
|---|---|
| 1 *pragmapush list | |
| 2 *pragma list | |
| 3 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
| 4 ; The error handler | |
| 5 ; | |
| 6 ; Enter with the error number in B. This routine will do some cleanup and handle any ON ERROR GOTO handler that | |
| 7 ; may be active. | |
| 8 ; | |
| 9 ; Note the error message lookup does not need to be efficient which is why the lookup just runs through the list | |
| 10 ; of error messages in sequence looking for NUL terminators. The specific handling of B (error number) below avoids | |
| 11 ; issues if there happen to be error codes above 128. | |
| 12 ERROR clr filenum ; reset display device to console | |
| 13 jsr writecondnl ; do a newline if needed (will preserve B) | |
| 14 ldx #errormsg ; point to error message list | |
| 15 incb ; account for decb below | |
| 16 bra ERROR1 ; go search for correct message | |
| 17 ERROR0 lda ,x+ ; end of message? | |
| 18 bne ERROR0 ; brif not end of message | |
| 19 ERROR1 decb ; at the correct one? | |
| 20 bne ERROR0 ; brif not - skip to next one | |
| 21 ERROR2 jsr writestrconduc ; output error message | |
| 22 ldu curline ; are we in immediate mode? | |
| 23 beq ERROR3 ; brif so | |
| 24 ldx #inmsg ; point to " in " | |
| 25 jsr writestrconduc ; output " in " | |
| 26 ldd 2,u ; get line number | |
| 27 jsr print_uint16d ; display the line number | |
| 28 ERROR3 lds freetop ; reset the stack pointer (error routine could be called anywhere) | |
| 29 clr ,-s ; reset the call stack | |
| 30 sts stackptr | |
| 31 jmp immediate ; go back to immediate mode | |
| 32 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
| 33 ; Error messages | |
| 34 ; | |
| 35 ; Each error begins with a deferr macro invocation which will define a symbol err_slug with the next error number | |
| 36 ; | |
| 37 ; deferr slug | |
| 38 ; | |
| 39 ; This is then followed by the error message defined with fcn. | |
| 40 ; | |
| 41 ; Real error numbers start at 1; 0 is used to indicate no error. | |
| 42 *pragmapush list | |
| 43 *pragma nolist | |
| 44 __errnum set 0 | |
| 45 deferr macro noexpand | |
| 46 err_{1} equ __errnum | |
| 47 __errnum set __errnum+1 | |
| 48 endm | |
| 49 *pragmapop list | |
| 50 errormsg deferr none | |
| 51 fcn 'No error' | |
| 52 deferr nf | |
| 53 fcn 'NEXT without FOR' | |
| 54 deferr sn | |
| 55 fcn 'Syntax error' | |
| 56 deferr ul | |
| 57 fcn 'Undefined line number' | |
| 58 deferr rg | |
| 59 fcn 'RETURN without GOSUB' | |
| 60 deferr ov | |
| 61 fcn 'Overflow' | |
| 62 deferr tm | |
| 63 fcn 'Type mismatch' | |
| 64 *pragmapop list |