All Change
Conversion To NAS-SYS
By Richard Beal
Many readers have requested a table showing equivalent codes
for old monitors and for Nas-Sys. Many new INMC members have only ever
used Nas-Sys, and have come across old programs they wish to convert.
Derek Brough has made a tremendous effort in converting the T4 library
to Nas-Sys, so you will find it easier to get some of these programs
from the new Nas-Sys machine code program library.
To keep the table simple we have compared T4 to Nas-Sys. The
older T2 and B-Bug monitors were subsets of T4, so the conversion works
in the same way for them. It is not possible to show every detail
because there are so many small differences, in particular the method
of input and output.
| Name | Function performed | | T4 | Nas-Sys |
|---|
| RIN | Get input character | | CD 3E 00 | CF |
| ROUT | Output a character | | CD 4A 0C | F7 |
| | or | F7 | |
| | or | CD 3B 01 | |
| PRS | Print a string | | EF …00 | EF…00 |
| RCAL | Relative call | | D7 .. | D7 .. |
| SCAL | Subroutine call | | NONE | DF .. |
| RDEL | Delay | | FF | FF |
| | or | CD 35 00 | |
| BRKPT | Breakpoint | | E7 | E7 |
| START | Reset computer | | C7 | C7 |
| MRET | Return to montior | | C3 86 02 | DF 5B |
| | or | CF | |
| TDEL | Long delay | | NONE | DF 5D |
| FFLP | Flip bits in port 0 | | CA 4A 00 | DF SE |
| MFLP | Flip tape drive LED | | CD 51 00 | DF 5F |
| ARGS | Load arguments | | CD 97 06 | DF 60 |
| IN | Scan for input character | | CD 4D 0C | DF 62 |
| | or | CD 69 00 | |
| INLIN | Obtain input line | | NONE | DF 63 |
| NUM | Convert from ASCII to binary | | CD 5A 02 | DF 64 |
| TBCD3 | Output HL in ASCII | | CD 32 02 | DF 66 |
| TBCD2 | Output A in ASCII | | CD 2B 02 | DF 67 |
| B2HEX | Output A in ASCII | | CD 44 02 | DF 68 |
| SPACE | Output space | | CD 3C 02 | DF 69 |
| CRLF | Output carriage return | | CD 40 02 | DF 6A |
| ERRM | Output error message | | NONE | DF 6B |
| TX1 | Output HL,DE in ASCII | | CD 5B 04 | DF 6C |
| SOUT | String of characters to serial output | | CD CC 06 | DF 6D |
| SRLX | Character to serial output | | CD 5D 00 | DF 6F |
| | or | CD 5E 00 | |
| RLIN | Get arguments from input line | | NONE | DF 79 |
| B1HEX | Output half of A in ASCII | | CD 4D 02 | DF 7A |
| BLINK | Blink cursor, get input | | NONE | DF 7B |
| CPOS | Find start of line | | NONE | DF 7C |