-;;; Managing a memory area for temporary objects
-;;;
-;;; A temporary object space is allocated from the current usage
-;;; level, or cycling back to be from the lowest space address when
-;;; the requested size exceeds the space edge.
+;;; Managing a memory area for temporary "objects".
;;;
+;;; Object space is allocated cyclically, starting subsequent to prior
+;;; allocation and cycling back when requested object size exceeds
+;;; the space edge. The "inital" part, which starts as empty, is
+;;; considered "held" space that is not reused when cycling back, and
+;;; apart from allowing for this, the space management is left open.
+
WORD p_objectspace,'TEMPSPACE',dovariable
;; Holds size and address of the object space.
- dq 104857600 ; [0] Total object space size (request size)
- dq 0 ; [8] Object space base address
+ dq 1073741824 ; [0] Total object space size (request size)
+ dq 0 ; [8] Object space base address.
dq 0 ; [16] Currently used.
+ WORD p_tempheld,'TEMPHELD',dovariable
+ ;; ( -- a )
+ ;; Marks the barrier for "held space"
+ dq 0 ; [24] Currently held.
+
WORD p_temp,'TEMP',fasm
;; ( size -- addr )
;; Allocate an object of given size
add rax,qword [p_objectspace_DFA+16]
cmp rax,qword [p_objectspace_DFA]
jl p_objecthole_from_tail
- mov qword [p_objectspace_DFA+16],0
- mov rax,qword [rsp]
+ mov rax,qword [p_tempheld_DFA] ; cycling back to here
+ mov qword [p_objectspace_DFA+16],rax
+ add rax,qword [rsp]
p_objecthole_from_tail:
;; rax = new usage count
mov rbx,qword [p_objectspace_DFA+16]
- mov qword [p_objectspace_DFA+16],rax
add rbx,qword [p_objectspace_DFA+8]
mov qword [rsp],rbx
+ mov qword [p_objectspace_DFA+16],rax
popr rsi
next