On Tue, 15 May 2012 20:07:52 +0000, Robert Prins wrote: >maybe a 16-byte >three-instruction sequence like > >003FC0 E310 DF10 0158 003120 | LY r1,<a1:d7952:l4>(,r13,7952) >003FC6 E300 1047 0015 003120 | LGH r0,_shadow20(,r1,71) >003FCC 4000 E064 003120 | STH r0,_shadow20(,r14,100) > >is really faster than the simple 6-byte one-instruction sequence > >0026D4 D2 01 7 064 6 047 MVC REPT_LINE.DATE.MONTH(2),REPT_LIST.DATE.MONTH
Not likely. Address Generation Interlock (AGI) will cause the second instruction to stall until the address is available in R1. In addition, instruction cracking will, under some circumstances, cause a z196 processor to execute a load and a store when a MVC instruction is executed. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN