.bp .NH Appendix B: Translation of a \fBPAR\fP construct to EM code using the library routines to simulate parallelism .PP Translation of the parallel construct: .DS .ft CW par P0 par i = [ 1 for n ] P(i) .DE is .TS center; lf5 lf5. lal -20 ; Assume 20 bytes of local variables at this moment cal $parbegin ; Set up a process group asp 4 ; Assume pointersize = 4 cal $parfork ; Split stack in two from local -20 lfr 4 ; Assume wordsize = 4 zne *23 ; One end jumps to second process, other continues here lor 0 ; Static link cal $P0 asp 4 bra *24 ; Jump to the outer parend 23 cal $parfork ; Fork off `par i = ...' process lfr 4 zne *25 ; One end jumps to end of outer par lal -20 ; Place break just above i cal $parbegin ; Set up another process group for the P(i) loc 1 stl -24 ; i:=1 lol n ; Assume n can be addressed this simply stl -28 ; A nameless counter bra *26 ; Branch to counter test 27 cal $parfork ; Fork off one P(i) lfr 4 zne *28 ; One jumps away to increment i, the other calls P(i) lol -24 lor 0 cal $P asp 8 bra *29 28 inl -24 ; i:=i+1 del -28 ; counter:=counter-1 26 lol -28 zgt *27 ; while counter>0 repeat loop 29 cal $parend ; Wait for the P(i) to finish, then delete group bra *24 ; Jump to the higher up meeting place with P0 25 ; Note that the bra will be optimized away 24 cal $parend ; Wait for both processes to end, then delete group .TE