Convert MRJE to Character (CVTMC)

Op Code (Hex)	Extender	Operand 1	Operand 2	Operand 3	Operand [4-5]
CVTMC 10AB		Receiver	Controls	Source

CVTMCB 1CAB	Branch options	Receiver	Controls	Source	Branch targets

CVTMCI 18AB	Indicator options	Receiver	Controls	Source	Indicator targets

Operand 1: Character variable scalar.

Operand 2: Character(6) variable scalar.

Operand 3: Character scalar.

Operand 4-5:

Branch Form-Branch point, instruction pointer, relative instruction number, or absolute instruction number.
Indicator Form-Numeric variable scalar or character variable scalar.

Bound program access

Built-in number for CVTMC is 132.
CVTMC (
       receiver          : address
       receiver_length   : unsigned binary(4)
       controls          : address
       source            : address
       source_length     : unsigned binary(4)
       return_code       : address of signed binary(4)
)

The return_code will be set as follows:

Return code	Meaning
`-1`	Receiver Overrun.
`0`	Source Exhausted.

The receiver, controls and source parameters correspond to operands 1, 2 and 3 on the CVTMC operation.

The receiver_length and source_length parameters contain the length, in bytes, of the receiver and source strings. They are expected to contain values between 1 and 32,767.

The return_code parameter is used to provide support for the branch and indicator forms of the CVTMC operation. The user must specify code to process the return_code and perform the desired branching or indicator setting.

Description

This instruction converts a character string from the MRJE (MULTI-LEAVING remote job entry) compressed format to character format. The operation converts the source (operand 3) from the MRJE compressed format to character format under control of the controls (operand 2) and places the results in the receiver (operand 1).

The source and receiver operands must both be character strings. The source operand cannot be specified as either a signed or unsigned immediate value.

The controls operand must be a character scalar that specifies additional information to be used to control the conversion operation. It must be at least 6 bytes in length and have the following format:

Offset
Dec	Hex	Field Name		Data Type and Length
0	0	Controls operand		Char(6)
0	0		Receiver offset		Bin(2)
2	2		Source offset		Bin(2)
4	4		Algorithm modifier		Char(1)
5	5		Receiver record length		Char(1)
6	6	--- End ---

As input to the instruction, the source offset and receiver offset fields specify the offsets where bytes of the source and receiver operands are to be processed. If an offset is equal to or greater than the length specified for the operand it corresponds to (it identifies a byte beyond the end of the operand), a template value invalid (hex 3801) exception is signaled. As output from the instruction, the source offset and receiver offset fields specify offsets that indicate how much of the operation is complete when the instruction ends.

The algorithm modifier has the following valid values:

Hex 00 = Do not move SRCBs (sub record control bytes) from the source into the receiver.
Hex 01 = Move SRCBs from the source into the receiver.

The receiver record length value specifies the record length to be used to convert source records into the receiver operand. This length applies to only the string portion of the receiver record and does not include the optional SRCB field. If a receiver record length of 0 is specified, a template value invalid (hex 3801) exception is signaled.

Only the first 6 bytes of the controls operand are used. Any excess bytes are ignored.

The operation begins by accessing the bytes of the source operand at the location specified by the source offset. This is assumed to be the start of a record. The bytes of the records in the source operand are converted into the receiver operand at the location specified by the receiver offset according to the following algorithm.

The first byte of the source record is considered to be an RCB (record control byte) that is to be ignored during conversion.

The second byte of the source record is considered to be an SRCB. If an algorithm modifier of value hex 00 was specified, the SRCB is ignored. If an algorithm modifier of value hex 01 was specified, the SRCB is copied into the receiver.

The strings to be built in the receiver record are described in the source after the SRCB by one or more SCBs (string control bytes).

The format of the SCBs in the source are as follows:

o k l jjjjj

The bit meanings are:

Bit	Value	Meaning
o	0	End of record;the EOR SCB is hex 00.
	1	All other SCBs.
k	0	The string is compressed.
	1	The string is not compressed.
l		For k = 0:
	0	Blanks (hex 40s) have been deleted.
	1	Nonblank characters have been deleted. The next character in the data stream is the specimen character.
		For k = 1:
		This bit is part of the length field for length of uncompressed data.
jjjjj		Number of characters that have been deleted if k = 0. The value can be 1-31.
ljjjjj		Number of characters to the next SCB (no compression) if k=1. The value can be 1-63.
		The uncompressed (nonidentical bytes) follow the SCB in the data stream.

A length of 0 encountered in an SCB results in the signaling of a conversion (hex 0C01) exception.

Strings of blanks or nonblank identical characters described in the source record are repeated in the receiver the number of times indicated by the SCB count value.

Strings of nonidentical characters described in the source record are moved into the receiver for the length indicated by the SCB count value.

When an EOR (end of record) SCB (hex 00) is encountered in the source, the receiver is padded with blanks out to the end of the current record.

If the converted form of a source record is larger than the receiver record length, the instruction is terminated by signaling a length conformance (hex 0C08) exception.

If the end of the source operand is not encountered, the operation then continues by reapplying the above algorithm to the next record in the source operand.

If the end of the source operand is encountered (whether or not in conjunction with a record boundary, EOR SCB in the source), the instruction ends with a resultant condition of source exhausted. The receiver offset locates the byte following the last fully converted record in the receiver. The source offset locates the byte following the last source record for which conversion is complete. The value of the remaining bytes in the receiver after the last converted record are unpredictable.

If the converted form of a record cannot be completely contained in the receiver, the instruction ends with a resultant condition of receiver overrun. The receiver offset locates the byte following the last fully converted record in the receiver. The source offset locates the byte following the last source record for which conversion is complete. The value of the remaining bytes in the receiver after the last converted record is unpredictable.

If the source exhausted and the receiver overrun conditions occur at the same time, the source exhausted condition is recognized first. In this case, the receiver offset may contain a value equal to the length specified for the receiver which causes an exception to be signaled on the next invocation of the instruction. The processing performed for the source exhausted condition provides for this case if the instruction is invoked multiple times with the same controls operand template. When the receiver overrun condition is the resultant condition, the source always contains data that can be converted.

Limitations (Subject to Change)

The following are limits that apply to the functions performed by this instruction.

Any form of overlap between the operands on this instruction yields unpredictable results in the receiver operand.

Resultant Conditions

Source exhausted - All full records in the source operand have been converted into the receiver operand.
Receiver overrun - An overrun condition in the receiver operand was detected prior to processing all of the bytes in the source operand.

Authorization Required

None

Lock Enforcement

None

Exceptions

06 Addressing

0601 Space Addressing Violation
0602 Boundary Alignment
0603 Range

08 Argument/Parameter

0801 Parameter Reference Violation

0C Computation

0C01 Conversion
0C08 Length Conformance

10 Damage Encountered

1004 System Object Damage State
1044 Partial System Object Damage

1C Machine-Dependent

1C03 Machine Storage Limit Exceeded

20 Machine Support

2002 Machine Check
2003 Function Check

22 Object Access

2201 Object Not Found
2202 Object Destroyed
2203 Object Suspended
2208 Object Compressed
220B Object Not Available

24 Pointer Specification

2401 Pointer Does Not Exist
2402 Pointer Type Invalid

2C Program Execution

2C04 Branch Target Invalid

2E Resource Control Limit

2E01 User Profile Storage Limit Exceeded

32 Scalar Specification

3201 Scalar Type Invalid

36 Space Management

3601 Space Extension/Truncation

38 Template Specification

3801 Template Value Invalid

44 Protection Violation

4401 Object Domain or Hardware Storage Protection Violation
4402 Literal Values Cannot Be Changed