Open the Old Registers window with the OREGS command. Close it by issuing the OREGS command again or by issuing the CLOSE command against that window.

 ┌01─Old Registers────────────────────────────────────────────────────────────┐
 │ (TCAT) @PROLOG+82                       PSW 078D200080057748 (CC mask=2 H) │
 │ 00057748 1836                       LR    R3,R6                            │
 │  R0 00009025  R1 000120D4  R2 00057FC0  R3 FEFE030F FPR0 0000000000000000  │
 │  R4 FEFE040F  R5 FEFE050F  R6 00000001  R7 00000002 FPR2 0000000000000000  │
 │  R8 00000000  R9 000577E8 R10 FEFE0A0F R11 FEFE0B0F FPR4 0000000000000000  │
 │ R12 800576E0 R13 00012130 R14 000145CC R15 800576E0 FPR6 000000000000000   │
 └────────────────────────────────────────────────────────────────────────────┘

If your program has executed one or more instructions, by default, a copy of the PSW, next instruction, and registers as of the last time IDF was in control are also shown (after this these are generally the previous contents of the PSW, general registers, and so on). If the CREGS command or the AREGS command was issued, the control registers or the access registers, as of the last time IDF was in control, are displayed. If your program has not executed any instructions, this window is empty.