Resending as the original, nicely formatted post, was rejected because HTML.
Just for sharing..
The following simple C function:
int asmFunct(void *asmFunctPtr, void *asmFunctParms) {
int functRC;
__asm(" L 15,%1 \n"
" LR 1,%2 \n"
" BALR 14,15 \n"
" ST 15,%0 "
:"=m"(functRC)
:"m"(asmFunctPtr), "r"(asmFunctParms)
:"r1", "r14", "r15");
return 0;
}
When compiled under z/OS 2.4 without optimization:
SOURCE,XREF,SSCOM,LIST,LANGLVL(EXTENDED),LONGNAME,ASM,RENT
Is properly translated to (Prolog and Epilog code omitted):
0000E4 End of Prolog
0000E4 5010 D09C 000001 | ST r1,#SR_PARM_1(,r13
000002 | *
000003 | * int functRC;
000004 | *
000005 | * __asm(" L 15,%1 \n"
0000E8 5820 D09C 000005 | L r2,#SR_PARM_1(,r13
0000EC 5840 2004 000005 | L r4,asmFunctParms(,
0000F0 58F2 0000 000005 | L r15,0(r2,)
0000F4 1814 000005 | LR r1,r4
0000F6 05EF 000005 | BALR r14,r15
0000F8 50FD 0098 000005 | ST r15,152(r13,)
000006 | * " LR 1,%2 \n"
000007 | * " BALR 14,15 \n"
000008 | * " ST 15,%0 "
000009 | * :"=m"(functRC)
000010 | * :"m"(asmFunctPtr),
"r"(asmFunctParms)
000011 | * :"r1", "r14", "r15");
000012 | * return 0;
0000FC 41F0 0000 000012 | LA r15,0
000013 | * }
000100 000013 | @1L1 DS 0H
000100 Start of Epilog
When using optimization (any level), the entire __asm statement is removed
leading to incorrout.
SOURCE,XREF,SSCOM,LIST,LANGLVL(EXTENDED),LONGNAME,ASM,RENT,OPT(3)
0000DE End of Prolog
000002 | *
000003 | * int functRC;
000004 | *
000005 | * __asm(" L 15,%1 \n"
000006 | * " LR 1,%2 \n"
000007 | * " BALR 14,15 \n"
000008 | * " ST 15,%0 "
000009 | * :"=m"(functRC)
000010 | * :"m"(asmFunctPtr),
"r"(asmFunctParms)
000011 | * :"r1", "r14", "r15");
000012 | * return 0;
0000DE 41F0 0000 000012 | LA r15,0
000013 | * }
0000E2 000013 | @1L1 DS 0H
0000E2 Start of Epilog
This is with:
5650ZOS V2.4 z/OS XL C
CCN0000(I) Product(5650-ZOS) Phase(CCNEOPTP) Level(D210317.Z2R4)
CCN0000(I) Product(5650-ZOS) Phase(CCNDRVR ) Level(D210317.Z2R4)
CCN0000(I) Product(5650-ZOS) Phase(CCNEP ) Level(D210317.Z2R4)
CCN0000(I) Product(5650-ZOS) Phase(CCNETBY ) Level(D210317.Z2R4)
CCN0000(I) Product(5650-ZOS) Phase(CCNECWI ) Level(D210317.Z2R4)
And makes it unreliable to optimize C programs embedding assembler code..
I hope this helps,
mario
