The BBC and Master Computer Public Domain Library
9042 NEW
Submitted by Steve Fewell
Description:
Call routine &9C6A to check that the BASIC statement is correct and ends correctly
-
[&9045] Call routine &BF3E to carry out the NEW command as follows:
- * Set TOP (&12-&13) to PAGE (&18, LSB of PAGE is always zero)
- * Set TRACE flag (&20) to 0 (meaning that TRACE is OFF)
- * Store #&0D as the first byte of the program, i.e. the '<cr>' character
- * Store #&FF as the second byte of the program (previously this byte contained the line number MSB value)
- These 2 characters specify a null program ('<cr>' specifies program start and #&FF specifies program end)
- * Set TOP to point to the next byte after these two characters
- * Set TRACE flag (&20) to 0 (meaning that TRACE is OFF)
execute any entered commands.
Disassembly for the NEW routine
j |
032 106 156 |
20 6A 9C |
JSR &9C6A Check end of Statement | |
> |
032 062 191 |
20 3E BF |
JSR &BF3E Reset the program to an empty program | |
9048 |
|
|
|
... Prompt for command line and execute the entered command(s) ... |
&BF3E - reset the program to an empty program
|
169 013 |
A9 0D |
LDA#&0D |
|
BF40 |
|
164 024 |
A4 18 |
LDY &18 |
BF42 |
|
132 019 |
84 13 |
STY &13 |
BF44 |
d |
100 018 |
64 12 |
STZ &12 |
BF46 |
d |
100 032 |
64 20 |
STZ &20 |
BF48 |
|
146 018 |
92 12 |
STA (&12) |
BF4A |
|
169 255 |
A9 FF |
LDA#&FF |
BF4C |
|
160 001 |
A0 01 |
LDY#&01 |
BF4E |
|
145 018 |
91 12 |
"STA (&12),Y" |
BF50 |
|
200 |
C8 |
INY |
BF51 |
|
132 018 |
84 12 |
STY &12 |
BF53 |
` |
96 |
60 |
RTS |
