Convert from zoned format to decimal floating point format

摘要

Machine instructions, referred to herein as a long Convert from Zoned instruction (CDZT) and extended Convert from Zoned instruction (CXZT), are provided that read EBCDIC or ASCII data from memory, convert it to the appropriate decimal floating point format, and write it to a target floating point register or floating point register pair. Further, machine instructions, referred to herein as a long Convert to Zoned instruction (CZDT) and extended Convert to Zoned instruction (CZXT), are provided that convert a decimal floating point (DFP) operand in a source floating point register or floating point register pair to EBCDIC or ASCII data and store it to a target memory location.

主权项

1. A computer program product for executing a machine instruction in a central processing unit, the computer program product comprising:
a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:
obtaining, by a processor, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising:
at least one opcode field to provide an opcode, the opcode identifying a convert from zoned to decimal floating point function;a first register field designating a first operand location;a second register field and a displacement field, wherein contents of a second register designated by the second register field are combined with contents of the displacement field to form an address of a second operand; anda sign control used to indicate whether the second operand has a sign field; andexecuting the machine instruction, the executing comprising:
converting the second operand in a zoned format to a decimal floating point format, wherein the converting comprises:
converting one or more triplets of zoned digits in the second operand to a corresponding one or more densely packed decimal groups, the corresponding one or more densely packed decimal groups provided as a first portion of a result; andconverting a remaining zoned digit in the second operand to a corresponding bit sequence, the corresponding bit sequence being provided as a second portion of the result; andplacing the result in the first operand location, wherein the result is stored to the location in the decimal floating point format absent issuing one or more additional machine instructions to convert to the decimal floating point format.