Paul Gilmartin wrote:
Consider:
/* I do this all the time... */
do phonyblock = 1 for 1
...
if Bailout then leave phonyblock
...
end phonyblock
o I put a "name = 1 for 1" on all my large blocks, and use a
matching "end name"
- the interpreter checks that my "end"s match my "do"s.
- but it's a kludge because I can't name the "end" nor the
"leave" without introducing a phony control variable.
Structured HLASM provides a "simple" DO for this need. For example:
| ************************************
| * Program Main Line *
| ************************************
| DO ,
| JAS R14,Routine1
| DOEXIT LTR,R15,R15,NZ
| JAS R14,Routine2
| DOEXIT LTR,R15,R15,NZ
| .
| . (more routine calls)
| .
| ENDDO ,
These can, of course, be named and nested -- no dummy control variable
required:
| DO LABEL=ThisIsTheNameOfMyOuterDo
| DO LABEL=ThisIsTheNameOfMyInnerDo
| .
| .
| LEAVE ThisIsTheNameOfMyOuterDo
| .
| .
| ENDDO , ThisIsTheNameOfMyInnerDo
| .
| . More logic here
| .
| ENDDO , ThisIsTheNameOfMyOuterDo
One nice feature is that any "labels" you choose are actually exposed --
as coded -- within the HLASM name space. This means you can use them to
produce the most efficient code possible for frequently-executed
routines. Consider this example, using TRE, I posted in another thread:
| LM R14,R15,0(R1) Load string ptr and its length
| LA R1,TRTSCRUB Ptr to translation table
| XR R0,R0 Set stop char = x'00'
| DO INF Do for translate
| TRE R14,R1 Translate the string
| DOEXIT Z Exit if no more data
| IF O If iterate needed
| ITERATE , Process more data
| ENDIF , EndIf
| MVC 0(1,R14),0(R1) Translate x'00' to whatever
| LA R14,1(,R14) Advance past stop character
| AHI R15,-1 Decrement length remaining
| DOEXIT NP Exit if no more data
| ENDDO , EndDo for translate
It should run slightly faster if I expose a DO label and code instead:
| LM R14,R15,0(R1) Load string ptr and its length
| LA R1,TRTSCRUB Ptr to translation table
| XR R0,R0 Set stop char = x'00'
| DO INF,LABEL=TreLoop Do for translate
| TRE R14,R1 Translate the string
| DOEXIT Z Exit if no more data
| JO TreLoop Branch if another segment
| MVC 0(1,R14),0(R1) Translate x'00' to whatever
| LA R14,1(,R14) Advance past stop character
| AHI R15,-1 Decrement length remaining
| DOEXIT NP Exit if no more data
| ENDDO , EndDo for translate
--
Edward E Jaffe
Phoenix Software International, Inc
5200 W Century Blvd, Suite 800
Los Angeles, CA 90045
310-338-0400 x318
[EMAIL PROTECTED]
http://www.phoenixsoftware.com/
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