The Convert to Binary instruction takes packed decimal data and converts it to 2’s complement integer data. Operand 1 designates a register where the result will be stored. Operand 2 represents a doubleword storage area which contains a valid 8-byte packed decimal integer.

CVB can convert any signed packed decimal integer in the range -2,147,483,648 and +2,147,483,647. If the doubleword specified in Operand 2 contains an integer outside this range, the 32 rightmost bits of the result are placed in the Operand 1 register and a fixed-point-divide exception is recognized.

In the following example, a packed field of length 4 is converted to binary.

ZAP DOUBWORD,XPACK MOVE PACKED NO TO DOUBLEWORD

CVB R5,DOUBWORD CHANGE IT TO BINARY

...

XPACK DC PL4’123’ X’0000123C’

DOUBWORD DS D

To convert XPACK to binary, we must first move it to a doubleword as required by the CVB instruction. At the end of the conversion, R5 contains x’0000007B’ = 123.

The diagram below illustrates the relationship between CVB and other data conversion instructions for some common data types.

Some Unrelated CVB Instructions

DOUBWORD DS D

PKD1 DC PL5’19’

PKD2 DC P’1865’

PKD3 DC P’-1’

ZAP DOUBWORD,PKD1 MOVE PACKED NO. TO STAGING AREA

CVB R8,DOUBWORD R8 = X’00000013’ = 19

ZAP DOUBWORD,PKD2 MOVE PACKED NO. TO STAGING AREA

CVB R8,DOUBWORD R8 = X’00000749’ = 1865

ZAP DOUBWORD,PKD3 MOVE PACKED NO. TO STAGING AREA

CVB R5,DOUBWORD R5 = X’FFFFFFFF’ = -1

ZAP DOUBWORD,=C’123’ DATA IS NOT PACKED

CVB R4,DOUBWORD ABEND - DATA MUST BE PACKED

ZAP DOUBWORD,=P’3,000,000,000’ DATA IS PACKED

CVB R4,DOUBWORD ABEND - FIXED PT. DIVIDE EXCEPTION

DATA > 2,147,483,647