IBM Version 4 manual Handling Exceptions in the MI Program

DCL	DD	RESULT	PKD(15,5)		BAS(RESULT@);
BRK	"ðððð1";
	CMPNV(B)	ARG1,ARG2	/	LO(ITS2);
	CPYNV	RESULT,ARG1;

BRETURN;

ITS2:

CPYNV

RESULT,ARG2;

BRK "ðððð2";

RETURN: RTX

\;

PEND;

This

allows

the HLL

programmer

to

use the

following

to

debug the

HLL

using

the

statement

identifiers

of

the

HLL:

STRDBG PGM(HLLEXAMPLE)

ADDBKP STMT(ðððð2) PGMVAR((RESULT ()))

The

following

display

shows

that

the

HLL

statement

00002

has been

equa

MI instruction

0005 due to

the

use

of

BRK

directives:

à

ð

Display Breakpoint

Statement/Instruction . . . . . . . . . : ðððð2 /ððð5

Program . . . . . . . . . . . . . . . . : HLLEXAMPLE

Recursion level . . . . . . . . . . . . : 1

Start position . . . . . . . . . . . . : 1

Format . . . . . . . . . . . . . . . . : \CHAR

Length . . . . . . . . . . . . . . . . : \DCL

Variable . . . . . . . . . . . . . . . : RESULT

Type . . . . . . . . . . . . . . . . : PACKED

Length . . . . . . . . . . . . . . . : 15 5

'6.ððððð'

Handling Exceptions in the MI Program

As coded, the MI01 program works fine when it is passed packed de ters. But when the MI01 program is passed other data types, such CL01 (abc 6), exceptions occur. To handle these exceptions, additiona ments could be added to MI01 so that:

ŸA 1-character return code parameter returnsð aindicstatuses whereno

	error	and1	indicates		an error		occurred.
Ÿ	An exception			description		is	defined to handle MCH1202 decimal data
Add	the	following statements				to	MI01:
1. Declare			a	fourth	space	parameter to receive the return code
	DCL	SPCPTR		RC@		PARM;

2. Update the operand list directive for PARM_LIST:

DCL	OL	PARM_LIST
		(ARG1@,
		ARG2@,
		RESULT@,
		RC@)	/\ the new parameter \/
		PARM	EXT;
3. Declare the		storage	addressed by RC@ as a 1-byte character
DCL	DD	RC	CHAR(1)	BAS(RC@);
			Chapter	7. Machine Interface Programming7-9