Tuesday, April 14, 2009

z390 znd zcobol now support Decimal Floating Point (DFP)

zcobol v1.5.00b now supports ANSI/ISO 754 Decimal Floating Point (DFP) plus ANSI/ISO 754 Binary Floating Point (BFP) .

zcobol supports the new explicit COBOL USAGE types defined in the draft COBOL 2008 standard: FLOAT-DECIMAL-7, FLOAT-DECIMAL-16, FLOAT- DECIMAL-34, FLOAT-BINARY-7, FLOAT-BINARY-16, FLOAT-BINARY-34. In addition the IBM mainframe default standard Hexadecimal Floating Point (HFP) is supported using FLOAT-HEX-7, FLOAT-HEX-15, and FLOAT-HEX-30. The COBOL 2002 standard generic floating point usage types FLOAT-SHORT, FLOAT-LONG, and FLOAT-EXTENDED default to DFP, but can be reassigned to any of the 3 types using zcobol option FLOAT(HEX), FLOAT(BINARY), or the default FLOAT(DECIMAL). The default for COMP-1 and COMP-2 in zcobol is HFP for IBM mainframe compatibility.

In addition to the floating point extended data types, zcobol now also supports the following COMP fields: half word S9(4), full word S9(9), double word S9(18), and quad word S9(39) and also packed decimal and zoned decimal up to S9(31).

The zcobol verbs MOVE, ADD, SUBTRACT, MULTIPLY, DIVIDE, IF, and DISPLAY support the above data types in any combination. zcobol generates HLASM IBM mainframe compatible code which can be run at native speed on IBM z9/z10 mainframes or the code can be compiled, linked, and executed on any J2SE platform including Windows and Linux using z390. The InstallShield download for z390 and zcobol which is open source is available on www.z390.org. For more information on zcobol visit www.zcobol.org. The download includes demos and new regression tests for the new data types.
The demo zcobol\demo\powers.cbl displays powers of 2 up to 126 using the new COMP S9(39) 128 bit integer support. The 3 regression tests zcobol\test\TESTHFP1.CBL, TESTBFP1, and TESTDFP1 using FLOAT(HEX), FLOAT(BINARY), and the default FLOAT(DECIMAL) respectively illustrate the new floating point code generation and execution capabilities.

Finally you can define a decimal floating point fraction such as 0.1 in COBOL and have it result in exactly 0.1000000 using DFP short versus 0.09999999 for HFP or BFP short due to irrational result in base 2 versus base 10.

Don Higgins