Zilog Z80380 - Manual (Page 33)

4-8
Z380 ™
U SER ' S M ANUAL
DC-8297-03
Z ILOG
4.2.7 Stack Pointer Relative Mode (SR) (Continued)
2. Load HL from location (SP – 4) in Extended mode, Long Word mode
SETC XM ;In Extended mode
DDIR LW ;operate next instruction in Long Word mode
LD HL, (SP–4) ;Load into the HL from the
;contents of the memory location
;whose address is four less than
;the contents of SP.
HLz HL SPz SP
Before instruction execution 1234 5678 07FF 7F00
After instruction execution EFCD AB89 07FF 7F00
Memory location 07FF7EFC 89
07FF7EFD AB
07FF7EFE CD
07FF7EFF EF
Address calculation: In Extended mode, FCH (–4 in Deci-
mal) encoding in the instruction is sign extended to a 32-
bit value before the address calculation, and calculation is
done in modulo 2
32 .
07FF7F00
+ FFFFFFFC
07FF7EFC
3. Load HL from location (SP + 10000H) in Extended mode, Long Word mode
SETC XM ;In Extended mode,
DDIR IW,LW ;operate next instruction in Long Word mode
;with a word immediate data.
LD HL, (SP+10000) ;Load into the HL from the
;contents of the memory location
;whose address is 10000H more than
;the contents of SP.
HLz HL SPz SP
Before instruction execution 1234 5678 07FF 7F00
After instruction execution EFCD AB89 07FF 7F00
Memory location 08007F00 89
08007F01 AB
08007F02 CD
08007F03 EF
Address calculation: In Extended mode, 010000H encod-
ing in the instruction is sign extended to a 32-bit value
before the address calculation, and calculation is done in
modulo 2
32 .
07FF7F00
+ 00010000
08007F00