ZiLOG Z80-RIO Operating System User's Manual page 229

APPENDIX I
RIO MEMORY MANAGER
This appendix describes register contents before and after
a MEMMGR call. Appendix C has the MCZ and ZDS addresses
of MEMMGR. Example 3 of Appendix G includes calls to
MEMMGR to allocate and deallocate buffer space.
ALLOCATE
MEMMGR CALL:
(allocate)
Before
A=O
HL = lower address
DE = upper address
BC = required size
After MEMMGR CALL:
boundary
boundary
(bytes)
A=80 (operation complete)
HL = beginning address of hole
DE = ending address of hole
BC = size of hole (bytes)
A=4A (insufficient memory)
HL = beginning of largest hole within boundaries
BC = size of largest hole within boundaries (bytes)
(if BC=O, then HL=undefined)
DEALLOCATE
Before MEMMGR CALL:
A=l (deallocate)
HL = beginning address of hole
BC = hole size (bytes)
After MEMMGR CALL:
A=80 (operation complete)
A=43 (not all blocks in area were allocated)
I-I