A faster replacement for L R15,=A(EXTRN)

[d...@higgins.net]

All

 

With the recent HLASM and z390 support for 32 bit relocatible immediate fields, it appears that for amode 31, the IILF insert immediate instruction is a more efficient way to load a register with an external address than using the traditional L load instruction to fetch an address constant.  The 6 byte insert immediate instruction can replace 8 bytes for the load and address constant.  And the insert instruction avoids having to add base and displacement address and then load the separate address constant.  

 

Don Higgins

d...@higgins.net

www.donhiggins.org