01B7-PRINT-RUNTIME-ERR.md

01B7 Print Runtime error

Prints the Runtime error string which has the form:

Runtime error XXX at YYYY:ZZZZ

Where XXX is the error code. YYYY:ZZZZ is a FAR PTR address where the error is triggered. In most cases, the YYYY:ZZZZ address here is the return address when this subroutine is called. Because it continues to the terminate/exit code, it never returns to the subroutine that calls it.

SYS01B7: MOV AX,[ErrorAddr.Offset]
SYS01BA: OR AX,[ErrorAddr.Segment]
SYS01BE: JZ 01E9

This checks if there is a need to print the ErrorAddr above. If ErrorAddr is not set, e.g. 0000:0000, then immediately proceed to SYS:01E9 DOS Exit.

SYS01C0: MOV BX,024C
SYS01C3: CALL 01F0

Print Runtime error including the trailing whitespace using the SYS:01F0 Print string subroutine. SYS:01C0 is also an entry point for terminating the program with an ExitCode in AX.

SYS01C6: MOV AX,[ExitCode]
SYS01C9: CALL 01FE

Print the ExitCode in base 10 using the SYS:01FE Convert number subroutine.

SYS01CC: MOV BX,025B
SYS01CF: CALL 01F0

Print the at including both whitespace characters at the front and end of the " at " string using SYS:01F0

SYS01D2: MOV AX,[ErrorAddr.Segment]
SYS01D5: CALL 0218

Print the segment address YYYY in base 16 (hexadecimal) using the SYS:0218 Print digits subroutine.

SYS01D8: MOV AL,3A
SYS01DA: CALL 0232

Prints the : (colon) character as part of the YYYY:ZZZZ address using the SYS:0232 Print character subroutine.

SYS01DD: MOV AX,[ErrorAddr.Offset]
SYS01E0: CALL 0218

Print the offset address ZZZZ in base 16 (hexadecimal) using SYS:0218.

SYS01E3: MOV BX,0260
SYS01E6: CALL 01F0

Finally, print a . and the newline characters using SYS:01F0 Print String. The code continues to the SYS:01E9 DOS Exit subroutine.

Go back