The BBC and Master Computer Public Domain Library
9384 RENUMBER
Submitted by Steve Fewell
Description:
-
Call routine &934D to read the Starting Line Number and Line increment parameters (if any were specified) as follows:
- * Set the IWA to 10 (the default program starting Line Number)
- * Call routine &9B1E to detokenise and extract the line number at BASIC text pointer A location and store it
- in the IWA. If no line number was found at BASIC text pointer A then the IWA will retain
- the default value of 10.
- * Push the IWA value (the starting line number) to the BASIC stack
- * Set the IWA to 10 (the default line number increment)
- * If the next non-space character is not comma ',', then no line increment parameter has been specified, so call &9BB0
- to check that the statement is terminated correctly (with a ':', '<cr>' or 'ELSE-token'
- terminator character), [if not then a 'Syntax error' will be issued] and exit routine &934D.
- * Otherwise, call routine &9B1E to detokenise and extract the Line number value from the BASIC Text pointer A
- location and store it in the IWA. The IWA now contains the specified Line increment value.
- * If byte &2B of the IWA contains a non-zero value, then the increment value is more than 255, so issue error
- 'Silly', as the line increment cannot be more than 255.
- * If byte &2A (the LSB) of the IWA contains a zero value, then the increment value is zero, so issue error
- 'Silly', as the line increment cannot be zero.
- * Call &9BA6 to skip any space characters and check that the statement is terminated correctly (with a ':',
- '<cr>' or 'ELSE-token' terminator character), [if not then a 'Syntax error' will be
- issued] and exit routine &934D.
- * Call routine &9B1E to detokenise and extract the line number at BASIC text pointer A location and store it
size.
Retrieve the Start Line number from the BASIC stack and store it in locations &39-&3A (bytes &3B-&3C are
unused as the Integer should only be 2-bytes wide). This is the renumbered line number counter.
Call routine &BDE5 to check that the program can be read correctly ('Bad program' message is displayed if the program
cannot be correctly read).
Call routine &9373 to set locations &3B-&3C to point to TOP (the end of the program) and to set &37-&38 to
point to PAGE+1 (the start of the program ignoring the first '<cr>' character) and to set Y to 1.
Renumber - Phase 1: Store all current line numbers in the program in the free storage space after TOP
Use the free space after TOP (pointed to by &3B-&3C) to store a copy of all of of the Line numbers present in the
program (and to issue an error if there is not enough space to store this required informaton) as follows.
[&9392] Read the next character (offset 0) from the &37-&38 pointer.
If the character is negative (end of program reached) then jump to &93C4 (all line numbers are stored, so continue to
the main RENUMBER routine).
Store the character (the first byte of the Line Number) at the location pointed to by the &3B-&3C pointer, i.e. the
free space after the TOP of the program. Read the next character (offset 1) from the &37-&38 pointer and store this
character in the next free space pointed to by &3B-&3C (offset 1). This value is the second byte of the Line Number
value.
Add 2 to the &3B-&3C pointer (to point to the next free location after the program end).
Compare the &3B-&3C pointer address with HIMEM (stored in locations &06-&07). If &3B-&3C exceeds
(or is equal to) HIMEM then issue 'RENUMBER space' error (and terminate the RENUMBER operation).
Otherwise, call routine &947A to update &37-&38 to point to the start of the next program line.
Jump back to &9392 to copy the next program line number.
Renumber - Phase 2: Replace all line numbers in the program with the renumbered line numbers
[&93C4] Call routine &937B to set &37-&38 to point to PAGE + 1 and to set Y to 1.
[&93C7] Load the first character of the Line's Line number. If the character is negative (end of program reached) then
jump to &93E7 to start the next phase of the renumbering.
Replace the Line number on the current line with the next renumbered Line Number (from locations &39-&3A (storing
&3A first)).
Add the Step Size (&2A) to the renumbered Line Number counter (&39-&3A (&3A is the MSB)).
Correct the &39-&3A Line Number if it has exceeded 32767 (&7FFF) by resetting bit 7 to 0 (removing the &8000
value from the value). So &39-&3A now contains the next renumbered Line Number.
Call routine &947A to update &37-&38 to point to the start of the next program line.
Jump back to &93C7 to replace the next program line number.
Renumber - Phase 3: Replace all line number references in the program with the correct renumbered version
[&93E7] Set BASIC Text pointer A (&0B-&0C) to PAGE (&18, the start of the program code).
[&93ED] Load the first character (the Line Number) of the program line pointed to by &0B-&0C.
If the character is negative then we have reached the end of the program, so jump to &8F83 to initialise the BASIC
variable space (as we have just destroyed any previously defined variables by placing the old line number values after TOP)
and prompt for the user's next command line input - as the RENUMBER operation is complete.
Set Y (the line offset value) to 4 (so that the Line Number and line length byte values are ignored).
Zero location &2C (the quote toggle flag).
[&93F7] Read the next byte of the program line pointed to by the address in locations &0B-&0C (offset Y).
-
If &2C is zero (then we are not inside a quote) so:
- * If the character is '#&8D' (Line number token) then jump to &941B to renumber the line number (this routine
- is described below). This token usually follows a GOSUB, GOTO, THEN or ELSE keyword and is
- followed by the literal line number
- * If the character is '#&F4' [REM-token] then jump to &9412 to skip the rest of the current program line
- is described below). This token usually follows a GOSUB, GOTO, THEN or ELSE keyword and is
If the current character (that was read by &93F7) is a quote (") then EOR the character with &2C (to
toggle the flag value).
If the character is not '<cr>' (carriage return) then jump back to &93F7 to check the next character of the
program line.
[&9412] Otherwise, skip the line end and move on to the next line by Adding the value at offset 3 of the current line
(which is the line length value) to the &0B-&0C pointer [and set the &0A offset to 1] and jump back to &93ED
to check the next program line for line numbers to renumber.
Renumber the Line Number specified after the line number token ('#&8D')
[&941B] Now a line number token has been encountered within a program line. This routine will now renumber the line
number so that it addresses the correct renumbered line.
Call &9B2A to set the IWA to the Line Number (after the Line number token value -'&8D').
Call routine &9373 to set &3B-&3C to TOP and &37-&38 to PAGE+1.
[&9421] Load the character at the &37-&38 location.
-
If the character is negative then the end of the program has been reached without finding a matching program Line, so jump
to &945C to:
- * Print the text "Failed at "
- * Store A in &2B (the Line number MSB)
- * Store the character pointed to by &0B-&0C (the line number LSB) to location &2A
- * Call routine &A081 to display the line number (in the IWA) on the screen - this outputs the line number that
- contained the failed reference
- * Call routine &BA92 to output a new line
- * Jump to &9446 to Set Y to &0A (the current position of the program line in the phase 3 search) and jump to
- &93F7 to continue checking the next character of the program line (for further line number
- references.
- * Store A in &2B (the Line number MSB)
stored after the end of the program).
-
If the line numbers are not equal then the matching renumbered line has not yet been found so:
- * [&944A] Clear the carry flag (so that we don't add an extra 1 to the &37-&38 pointer)
- * Call routine &947A to update the &37-&38 pointer to point to the next program line (by adding the line
- length byte (offset 3 from the current &37-&38 start of line pointer) to the &37-&38
- pointer and reset Y to 1.
- * Add 2 to the &3B-&3C pointer (so that the pointer points to the next unrenumbered line number stored after
- the end of the program.
- * Jump back to &9421 to check the next line of the program for a match
- * Call routine &947A to update the &37-&38 pointer to point to the next program line (by adding the line
-
Otherwise (we have found a match), so store the new renumbered line number (from the &37-&38 pointer location)
in the current program position - to replace the reference with the renumbered reference - as follows:
- * Store the Line number MSB ((&37,&38)+1) in location &3D
- * Store the Line Number LSB (pointed to by (&37, &38)) in X register
- * Set Y = the BASIC Text Pointer A offset - 1
- * Set &39-&3A to the current &0B-&0C pointer location (i.e. the line containing the reference)
- * Call routine &8D62 to tokenise the Program Line Number (in X and &3D) and store it at the ((&39-&3A)+1)
- location
- * Set Y to the BASIC Text pointer A offset (&0A)
- * Jump to &93F7 to continue with the next character of the program line (pointed to by &0B-&0C)
- * Store the Line Number LSB (pointed to by (&37, &38)) in X register
Disassembly for the RENUMBER routine
| 934D | 169 010 | A9 0A | LDA#&0A | |
| 934F | 032 024 174 | 20 18 AE | JSR &AE18 Set IWA to the 8-bit value in A | |
| 9352 | 032 030 155 | 20 1E 9B | JSR &9B1E Detokenise the Line Number at PTR A & Set IWA to the Line Number value | |
| 9355 | & | 032 038 188 | 20 26 BC | JSR &BC26 Push IWA value to the BASIC Stack [pushi] |
| 9358 | 169 010 | A9 0A | LDA#&0A | |
| 935A | 032 024 174 | 20 18 AE | JSR &AE18 Set IWA to the 8-bit value in A | |
| 935D | 032 229 140 | 20 E5 8C | JSR &8CE5 Compare next non-space [PTR A] character with ',' | |
| 9360 | 208 014 | D0 0E | BNE 14 --> &9370 | |
| 9362 | 032 030 155 | 20 1E 9B | JSR &9B1E Detokenise the Line Number at PTR A & Set IWA to the Line Number value | |
| 9365 | + | 165 043 | A5 2B | LDA &2B |
| 9367 | S | 208 083 | D0 53 | BNE 83 --> &93BC 'Silly' error |
| 9369 | * | 165 042 | A5 2A | LDA &2A |
| 936B | O | 240 079 | F0 4F | BEQ 79 --> &93BC 'Silly' error |
| 936D | L | 076 166 155 | 4C A6 9B | JMP &9BA6 Skip spaces and check end of Statement |
| 9370 | L | 076 176 155 | 4C B0 9B | JMP &9BB0 Check for end of Statement |
| 9373 | 165 018 | A5 12 | LDA &12 | |
| 9375 | ; | 133 059 | 85 3B | STA &3B |
| 9377 | 165 019 | A5 13 | LDA &13 | |
| 9379 | < | 133 060 | 85 3C | STA &3C |
| 937B | 165 024 | A5 18 | LDA &18 | |
| 937D | 8 | 133 056 | 85 38 | STA &38 |
| 937F | 160 001 | A0 01 | LDY#&01 | |
| 9381 | 7 | 132 055 | 84 37 | STY &37 |
| 9383 | ` | 096 | 60 | RTS |
| 9384 | M | 032 077 147 | 20 4D 93 | JSR &934D Read Start line and line increment parameters |
| 9387 | 9 | 162 057 | A2 39 | LDX#&39 |
| 9389 | 032 008 189 | 20 08 BD | JSR &BD08 Pop Integer from Stack to Zero page address | |
| 938C | 032 229 189 | 20 E5 BD | JSR &BDE5 Check program can be read correctly ('Bad program' message if not) | |
| 938F | s | 032 115 147 | 20 73 93 | JSR &9373 Set &3B-&3C to TOP and &37-&38 to PAGE+1 |
| 9392 | 7 | 178 055 | B2 37 | LDA (&37) |
| 9394 | 0. | 048 046 | 30 2E | BMI 46 --> &93C4 |
| 9396 | ; | 146 059 | 92 3B | STA (&3B) |
| 9398 | 7 | 177 055 | B1 37 | LDA (&37),Y |
| 939A | ; | 145 059 | 91 3B | STA (&3B),Y |
| 939C | 8 | 056 | 38 | SEC |
| 939D | 152 | 98 | TYA | |
| 939E | e; | 101 059 | 65 3B | ADC &3B |
| 93A0 | ; | 133 059 | 85 3B | STA &3B |
| 93A2 | 144 002 | 90 02 | BCC 2 --> &93A6 | |
| 93A4 | < | 230 060 | E6 3C | INC &3C |
| 93A6 | 197 006 | C5 06 | CMP &06 | |
| 93A8 | < | 165 060 | A5 3C | LDA &3C |
| 93AA | 229 007 | E5 07 | SBC &07 | |
| 93AC | 176 005 | B0 05 | BCS 5 --> &93B3 'RENUMBER space' error | |
| 93AE | z | 032 122 148 | 20 7A 94 | JSR &947A Advance &37-&38 to point to the next Program Line |
| 93B1 | 128 223 | 80 DF | BRA -33 --> &9392 | |
| 93B3 | ... 'Silly' error... | |||
| 93BC | ... 'RENUMBER space' error... | |||
| 93C4 | { | 032 123 147 | 20 7B 93 | JSR &937B Set &37-&38 to PAGE+1 |
| 93C7 | 7 | 178 055 | B2 37 | LDA (&37) |
| 93C9 | 0 | 048 028 | 30 1C | BMI 28 --> &93E7 |
| 93CB | : | 165 058 | A5 3A | LDA &3A |
| 93CD | 7 | 146 055 | 92 37 | STA (&37) |
| 93CF | 9 | 165 057 | A5 39 | LDA &39 |
| 93D1 | 7 | 145 055 | 91 37 | STA (&37),Y |
| 93D3 | 024 | 18 | CLC | |
| 93D4 | 9 | 165 057 | A5 39 | LDA &39 |
| 93D6 | e* | 101 042 | 65 2A | ADC &2A |
| 93D8 | 9 | 133 057 | 85 39 | STA &39 |
| 93DA | 169 000 | A9 00 | LDA#&00 | |
| 93DC | e: | 101 058 | 65 3A | ADC &3A |
| 93DE | ) | 041 127 | 29 7F | AND#&7F |
| 93E0 | : | 133 058 | 85 3A | STA &3A |
| 93E2 | z | 032 122 148 | 20 7A 94 | JSR &947A Advance &37-&38 to point to the next Program Line |
| 93E5 | 128 224 | 80 E0 | BRA -32 --> &93C7 | |
| 93E7 | 165 024 | A5 18 | LDA &18 | |
| 93E9 | 133 012 | 85 0C | STA &0C | |
| 93EB | d | 100 011 | 64 0B | STZ &0B |
| 93ED | 160 001 | A0 01 | LDY#&01 | |
| 93EF | 177 011 | B1 0B | LDA (&0B),Y | |
| 93F1 | 0g | 048 103 | 30 67 | BMI 103 --> &945A |
| 93F3 | 160 004 | A0 04 | LDY#&04 | |
| 93F5 | d, | 100 044 | 64 2C | STZ &2C |
| 93F7 | 177 011 | B1 0B | LDA (&0B),Y | |
| 93F9 | , | 166 044 | A6 2C | LDX &2C |
| 93FB | 208 008 | D0 08 | BNE 8 --> &9405 | |
| 93FD | 201 141 | C9 8D | CMP#&8D | |
| 93FF | 240 026 | F0 1A | BEQ 26 --> &941B | |
| 9401 | 201 244 | C9 F4 | CMP#&F4 | |
| 9403 | 240 013 | F0 0D | BEQ 13 --> &9412 | |
| 9405 | 200 | C8 | INY | |
| 9406 | " | 201 034 | C9 22 | CMP#&22 |
| 9408 | 208 004 | D0 04 | BNE 4 --> &940E | |
| 940A | E, | 069 044 | 45 2C | EOR &2C |
| 940C | , | 133 044 | 85 2C | STA &2C |
| 940E | 201 013 | C9 0D | CMP#&0D | |
| 9410 | 208 229 | D0 E5 | BNE -27 --> &93F7 | |
| 9412 | 160 003 | A0 03 | LDY#&03 | |
| 9414 | 177 011 | B1 0B | LDA (&0B),Y | |
| 9416 | 032 244 155 | 20 F4 9B | JSR &9BF4 Add A to PTR A pointer (&0B,&0C) & set PTR A (&0A) offset to 1 | |
| 9419 | 128 210 | 80 D2 | BRA -46 --> &93ED | |
| 941B | * | 032 042 155 | 20 2A 9B | JSR &9B2A Detokenise Line Number at PTR A (without skip spaces or skip #&8D char) & Set IWA to the Line Number value |
| 941E | s | 032 115 147 | 20 73 93 | JSR &9373 Set &3B-&3C to TOP and &37-&38 to PAGE+1 |
| 9421 | 7 | 178 055 | B2 37 | LDA (&37) |
| 9423 | 07 | 048 055 | 30 37 | BMI 55 --> &945C |
| 9425 | ; | 178 059 | B2 3B | LDA (&3B) |
| 9427 | + | 197 043 | C5 2B | CMP &2B |
| 9429 | 208 031 | D0 1F | BNE 31 --> &944A | |
| 942B | ; | 177 059 | B1 3B | LDA (&3B),Y |
| 942D | * | 197 042 | C5 2A | CMP &2A |
| 942F | 208 025 | D0 19 | BNE 25 --> &944A | |
| 9431 | 7 | 177 055 | B1 37 | LDA (&37),Y |
| 9433 | = | 133 061 | 85 3D | STA &3D |
| 9435 | 7 | 178 055 | B2 37 | LDA (&37) |
| 9437 | 170 | AA | TAX | |
| 9438 | 164 010 | A4 0A | LDY &0A | |
| 943A | 136 | 88 | DEY | |
| 943B | 165 011 | A5 0B | LDA &0B | |
| 943D | 9 | 133 057 | 85 39 | STA &39 |
| 943F | 165 012 | A5 0C | LDA &0C | |
| 9441 | : | 133 058 | 85 3A | STA &3A |
| 9443 | b | 032 098 141 | 20 62 8D | JSR &8D62 Tokenise program line & store at location specified by &39-&3A (which is &0B-&0C) |
| 9446 | 164 010 | A4 0A | LDY &0A | |
| 9448 | 128 173 | 80 AD | BRA -83 --> &93F7 | |
| 944A | 024 | 18 | CLC | |
| 944B | z | 032 122 148 | 20 7A 94 | JSR &947A Advance &37-&38 to point to the next Program Line |
| 944E | ; | 165 059 | A5 3B | LDA &3B |
| 9450 | i | 105 002 | 69 02 | ADC#&02 |
| 9452 | ; | 133 059 | 85 3B | STA &3B |
| 9454 | 144 203 | 90 CB | BCC -53 --> &9421 | |
| 9456 | < | 230 060 | E6 3C | INC &3C |
| 9458 | 128 199 | 80 C7 | BRA -57 --> &9421 | |
| 945A | Z | 128 090 | 80 5A | BRA 90 --> &94B6 [JMP &8F83 Initialise & prompt for next command line] |
| 945C | 032 207 190 | 20 CF BE | JSR &BECF Print following text as a warning message & jump to address specified | |
| 945F | Failed at | 070 097 105 108 101 100 032 097 116 032 | 46 61 69 6C 65 64 20 61 74 20 | EQUS "Failed at " |
| 9469 | 177 | B1 | EQUB &B1 | |
| 946A | 011 | 0B | EQUB &0B | |
| 946B | + | 133 043 | 85 2B | STA &2B |
| 946D | 200 | C8 | INY | |
| 946E | 177 011 | B1 0B | LDA (&0B),Y | |
| 9470 | * | 133 042 | 85 2A | STA &2A |
| 9472 | 032 129 160 | 20 81 A0 | JSR &A081 Print Line Number on screen (width 0) | |
| 9475 | 032 146 186 | 20 92 BA | JSR &BA92 Start new output line | |
| 9478 | 128 204 | 80 CC | BRA -52 --> &9446 | |
| 947A | 200 | C8 | INY | |
| 947B | 7 | 177 055 | B1 37 | LDA (&37),Y |
| 947D | 160 001 | A0 01 | LDY#&01 | |
| 947F | e7 | 101 055 | 65 37 | ADC &37 |
| 9481 | 7 | 133 055 | 85 37 | STA &37 |
| 9483 | 144 003 | 90 03 | BCC 3 --> &9488 | |
| 9485 | 8 | 230 056 | E6 38 | INC &38 |
| 9487 | 024 | 18 | CLC | |
| 9488 | ` | 096 | 60 | RTS |
