mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-09 02:58:06 +11:00
26 lines
730 B
NASM
26 lines
730 B
NASM
|
; The Parameter stack (PS) is maintained by SP and the Return stack (RS) is
|
||
|
|
; maintained by IX. This allows us to generally use push and pop freely because
|
||
|
|
; PS is the most frequently used. However, this causes a problem with routine
|
||
|
|
; calls: because in Forth, the stack isn't balanced within each call, our return
|
||
|
|
; offset, when placed by a CALL, messes everything up. This is one of the
|
||
|
|
; reasons why we need stack management routines below.
|
||
|
|
;
|
||
|
|
; This return stack contain "Interpreter pointers", that is a pointer to the
|
||
|
|
; address of a word, as seen in a compiled list of words.
|
||
|
|
|
||
|
|
; Push value HL to RS
|
||
|
|
pushRS:
|
||
|
|
ld (ix), l
|
||
|
|
inc ix
|
||
|
|
ld (ix), h
|
||
|
|
inc ix
|
||
|
|
ret
|
||
|
|
|
||
|
|
; Pop RS' TOS to HL
|
||
|
|
popRS:
|
||
|
|
dec ix
|
||
|
|
ld h, (ix)
|
||
|
|
dec ix
|
||
|
|
ld l, (ix)
|
||
|
|
ret
|