On Tue, 5 Jun 2012 14:51:48 -0400, Robert A. Rosenberg wrote: >At 07:57 -0400 on 06/05/2012, Tom Marchant wrote about Re: Base registers: > >>By adding a few LOCTR instructions, all of the data can be grouped at >>the beginning of the program. If relative branches are used in the code, >>the base register is needed only for data and literals. >> >>MYCSECT CSECT >> USING *,R15 >> J BYID >>DATA LOCTR >>ID DC C'module-name' >>BASES DC A(MYCSECT) >> DC A(MYCSECT+4096) >> DC A(MYCSECT+2*4096) >> DC A(MYCSECT+3*4096) >>BYID DS 0H >>CODE LOCTR >> LM R9,R12,BASES >> DROP R15 >> USING MYCSECT,R9,R10,R11,R12 >>... >>DATA LOCTR >>* additional DC statements are coded here >> LTORG >> >>You can probably do with only one base register for the data. > >That BYID needs to be placed after the CODE LOCTR or you will be >jumping into your DATA area and a DC or the LTORG.
Right. Thanks for the correction. The above should be coded as: >>MYCSECT CSECT >> USING *,R15 >> J BYID >>DATA LOCTR >>ID DC C'module-name' >>BASES DC A(MYCSECT) >> DC A(MYCSECT+4096) >> DC A(MYCSECT+2*4096) >> DC A(MYCSECT+3*4096) >>CODE LOCTR >>BYID DS 0H >> LM R9,R12,BASES >> DROP R15 >> USING MYCSECT,R9,R10,R11,R12 >>... >>DATA LOCTR >>* additional DC statements are coded here >> LTORG -- Tom Marchant
