LOCKSAVE (displacement X'640') is a four-word save area used by the LOCK macro to save GR14, GR15, GRO, and GR1 if the SAVE option of the LOCK macro is specified. 10. SVCREGS
SVCREGS (displacement X'650') is a four-word save area used to save GR12
through GR15 at the time of an SVC interrupt.
Virtual and Real Control Block Status
Examine the virtual and real control blocks for more information on the status of
the CP system. Figure 68 on page 512 describes the relationship of the CP control
blocks; several are described in detail in the following paragraphs. For even more
detail on the following control blocks, refer to VM / SP Data Areas and Control
B lock Logic, Volume 1.
Introduction to Debugging 511

VI i PSA (Prefix Storage Are.)
- IV I ARama, ASYSVM =" SlO .......... n (,Il "= "'C n (,Il 0 '< = [ (II a "'C t:= "'"I 0' 0 t) (JQ lI':" "'"I til ::c a a S" (II "'"I 0 vt I j RDCBLOK II 0 e: = 'C 0.: '" (II RCHFIOB I II PERBLOK CCRTABLE CORSWPNT CORPGNT .. --- VMBLOK I VDEVBLOKs § B r ECBLOK VDEVIOER I VDEVRRB
VDEVEXTN VSPXBLOK VDEVCON VDEVSPL STOPBLOK VSPLCTL CONBUF VSPSFBLK CCWs TROBLOK SFBLOK TROBGPQ ...... A""'" =r--r-l I L_ ALOTBLOK .--- ALOSBLOK