Ed Jaffe's comments about z/OS alsi values are as usual entirely correct.
As usual too there are other contexts in which IBM publications discuss
architectural levels and use terminology derived from 'architecture' in
quite different ways. (Consistency is the hobgoblin of little minds; is it
not?)
What follows is an extract from the current (V3R5) z/OS Enterprise PL/I
Programming Guide. It defines the possible values---1,2,3,4,5,6---of this
compiler's ARCH parameter. (This compiler shares its code-generation
machinery with the corresponding release of the z/OS C compiler; and these
level values are thus applicable mutatis mutandis to it too.)
ARCH ( n ) The current values that may be specified for the ARCH level
are:
0 Produces code that is executable on all models.
1 Produces code that executes only on the following and follow-on models:
9021-520, 9021-640, 9021-660, 9021-740, 9021-820, 9021-860, and 9021-900
9021-xx1 and 9021-xx2 9672-Rx1, 9672-Rx2(G1), 9672-Exx, and 9672-Pxx.
2 Produces code that executes only on the following and follow-on models:
9672-Rx3(G2), 9672-Rx4(G3), 9672-Rx5(G4), and 2003Specifically, these
ARCH(2) machines and their follow-ons include the Branch Relative
instruction set (Branch Relative and Save - BRAS), and the Halfword
Immediate instruction set (for example, Add Halfword Immediate - AHI).
3 Produces code that executes only on the following and follow-on models:
9672-xx6 (G5) and 9672-xx7 (G6)Specifically, these ARCH(3) machines and
their follow-ons include a set of facilities for IEEE floating-point
representation, as well as 12 additional floating-point registers and some
new floating-point support instructions. 6 Enterprise PL/I for z/OS
Programming Guide
ARCH(3) (or higher) is required for execution of a program that uses IEEE
floating-point.
4 Produces code that uses instructions available on model 2064-100 (z/900)
in ESA/390 mode.. Specifically, these ARCH(4) machines support the LALR
instruction as well as the ALCR and SLBR instructions which are useful in
8-byte integer arithmetic.
5 Produces code that uses instructions available on model 2064-100 (z/900)
in z/Architecture mode. Specifically, these ARCH(5) machines and their
follow-ons include instructions such as NILL, NILH, OILL, OILH, LLILL and
LLILH.
6 Produces code that uses instructions available on the 2084-xxx models in
z/Architecture mode. Specifically, the compiler on these ARCH(6) machines
and their follow-ons may exploit the long-displacement instruction set. The
long-displacement facility provides a 20-bit signed displacement field in 69
previously existing instructions (by using a previously unused byte in the
instructions) and 44 new instructions. A 20-bit signed displacement allows
relative addressing of up to 524,287 bytes beyond the location designated by
a base register or base and index register pair and up to 524,288 bytes
before that location. The enhanced previously existing instructions
generally are ones that handle 64-bit binary integers. The new instructions
generally are new versions of instructions for 32-bit binary integers. The
new instructions also include v A LOAD BYTE instruction that sign-extends a
byte from storage to form a 32-bit or 64-bit result in a general register v
New floating-point LOAD and STORE instructions The long-displacement
facility provides register-constraint relief by reducing the need for base
registers, code size reduction by allowing fewer instructions to be used,
and additional improved performance through removal of possible
address-generation interlocks.
If you specify an ARCH value less than 2, the compiler will reset it to 2.
Note: The x in the model numbers above (such as 9672-Rx4 is a
wildcard and stands for any alphanumeric machine of that type, such as
9627-RA4).Note: Code that is compiled at ARCH(n) runs on machines in the
ARCH(m) group if and only if m >= n.
John Gilmore
Ashland, MA 01721-1817
USA
_________________________________________________________________
On the road to retirement? Check out MSN Life Events for advice on how to
get there! http://lifeevents.msn.com/category.aspx?cid=Retirement
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
