Z88 Developers' Notes
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The OS Push Frame Structure
This Stack Frame is the standard pushed frame before an OS call. With it the OS routine can get or alter the registers on input and output. This format is only useful for the OZ disassembly.

(IY+$10)= RET to caller
(IY+$0E)= s2s3 [Initial binding of segment 3 is (IY+$0E)]
(IY+$0C)= HL [L=(IY+$0C), H=(IY+$0D)]
(IY+$0A)= DE [E=(IY+$0A), D=(IY+$0B)]
(IY+$08)= BC [C=(IY+$08), B=(IY+$09)]
(IY+$06)= AF [F=(IY+$06), A=(IY+$07)]
(IY+$04)= OZ call address
(IY+$02)= s2s3 [Initial binding of segment 3 is (IY+$02)]
(IY+$00)= IY

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