The BBC and Master Computer Public Domain Library
Next non-space Char PTRB
Submitted by Steve Fewell
Routine: NextCharPTRB
Name: Next non-space Char PTRB
Starting Address: &8F92
Exit: Move past spaces in BASICs Text
Pointer B and return the next Character in the string. Y is the PTR B offset of the character
Description:
Reads past any space characters found at the current position in the PTRB.
Returns with the next non-space Character from PTRB in A, and with the PTRB
Offset pointing to this value.
Routine &8FA8 returns the next non-space character in PTRB, and also sets
the zero flag is the character is a comma (','), or clears the zero flag is the
character is not a comma.
Disassembly for the Next non-space Char PTRB routine
|
164 027 |
A4 1B |
LDY &1B |
|
8F94 |
|
230 027 |
E6 1B |
INC &1B |
8F96 |
|
177 025 |
B1 19 |
"LDA (&19),Y" |
8F98 |
|
201 032 |
C9 20 |
CMP#&20 |
8F9A |
|
240 246 |
F0 F6 |
BEQ -10 --> &8F92 |
8F9C |
` |
96 |
60 |
RTS |
Get Next non-space Char PTRB and compare with ','
|
032 146 143 |
20 92 8F |
JSR &8F92 |
|
8FAB |
"," |
201 044 |
C9 2C |
CMP#&2C |
8FAD |
` |
96 |
60 |
RTS |
