| CC1F
to CC80 |
Subroutine, called by GOTO and GOSUB. It
searches for an inputted line number or matching label. A
successful search results in the line number being copied
to location 1,2. If the label address is already known
this is copied to 58,59. Otherwise the label is searched
for and then stored in the label store as well as being
copied to 58,59. |
| CC81
to CCD1 |
Execute INPUT.
CC8E is the entry point for a numeric variable INPUT, and
CCB6 for a string variable. Both entries call the BASIC
input routine at CD09 (q.v.); the inputted data is then
copied or read from the string input buffer at 140
onwards (see example program at back). |
| CCD2
to CCEF |
Execute UNTIL.
CCD2 calls the routine at C70C (the truth tester).
CCD5 - checks for a zero value of the DO/UNTIL stack
pointer as 13. If zero, this is an UNTIL with no DO
error.
CCE5 - pull the corresponding return address from data. |
| CCF0
to CD08 |
Execute DO.
CCF0 checks the value of the DO/UNTIL stack pointer at 13
for range, and causes an error if out of range (too many
DO/UNTIL loops).
CCFA - saves the DO/UNTIL return address. |
| CD09
to CD58 |
A very useful subroutine, to execute
inputs. Entry at CD09 prints a '?' on the screen and then
waits for keypresses. Entries are stored in the string
input buffer at 140 onwards, and full editing is allowed.
The routine returns when <CR> key is pressed, with
the Y register pointing at the last character inputted.
Entry at CD0F prints the contents of the accumulator as
an ASCII character (normally the > prompt sign), and
then stores keypresses in the direct-mode input buffer at
100 onwards. The value of COUNT (?7) is set to 0 on
return (see example program at back). |
| CD98
to CDBB |
Execute END. This effectively sets TOP
(?0D) and jumps to direct mode.
CD9B - set TOP=?12 (start of text area).
CDA5 - using TOP as a vector, find a carriage return
followed by a negative number, indicating end of program. |
| CDBC
to CDC8 |
A subroutine called by END which
executes:
TOP=TOP+Y register; Y register=1. |
| CDC9
to CE82 |
Routine to enter a BASIC program line
into the text area. On entry 16 and 25 contain the line
number being entered.
CE3E - A RAM test to see if there is enough to enter it. |
| CE83
to CEA0 |
A subroutine called by the command at
C406. |
| CEA1
to CEAD |
A subroutine which executes:
(58)=(58)+Y register; Y register=1. |
