ReAllocVec
Synopsis
newmemoryBlock = ReAllocVec(oldmemoryBlock, newsize, newattribute)
D0 A0 D0 D1C Prototype
ULONG *ReAllocVec(ULONG *oldmemoryBlock, ULONG newsize, ULONG newattribute);Description
Allows dynamic resizing of a memory area previously allocated via exec/AllocVec(). The new memory block can be larger or smaller than the previous one and can have new memory attributes.
If the newattribute parameter is left as NULL, the attributes of the old memory block will be used for the new allocation.
If the new memory block is smaller than the previous one, some data may be lost. This function copies the contents of oldmemoryBlock into the new memory block, up to the smaller of the two sizes.
Inputs
- oldmemoryBlock — The memory block to be resized.
- newsize — The new number of bytes to allocate.
- newattribute — Type of memory. If NULL, the memory type of
oldmemoryBlockwill be used.
Result
- newmemoryBlock — New address to use in place of
oldmemoryBlock. If NULL, it was not possible to allocate the new memory.
See Also
exec.library/AllocVec(), exec.library/FreeVec()
Implementation
The original 68020 assembly implementation:
; (29-Sep-1995) --- newmemoryBlock = ReAllocVec(oldmemoryBlock, newsize, newattr) (a0/d0/d1)
_LVOReAllocVec
movem.l d2-d7/a2-a6,-(sp)
move.l a0,a2 ; Save old memoryBlock
move.l d0,d2 ; Save new size
move.l ab_ExecBase(a6),a6 ; take exec.library base
;;;;;;;;jsr _LVOForbid(a6) ; multitasking off
addq.b #1,TDNestCnt(A6) ; FORBID
tst.l d1 ; no new attributes provided
bne.s MakeNewAlloc ; then use the old ones...
move.l a2,a1
jsr _LVOTypeOfMem(a6) ; retrieve old block attributes
move.l d0,d1 ; put them in D1
MakeNewAlloc
addq.l #4,d2
move.l d2,d0 ; new size memory block
jsr _LVOAllocMem(a6)
tst.l d0
beq.s RAVFail
move.l d0,a3 ; new memory Block
move.l d2,(a3)+ ; make AllocVec() function...
move.l -4(a2),d0 ; size old memoryBlock
cmp.l d2,d0 ; if old <= new then
ble.s CopySo ; if d0 <= d2 then
move.l d2,d0 ; copy as much as possible...
CopySo move.l a2,a0 ; old memoryBlock
move.l a3,a1 ; new memoryBlock
jsr _LVOCopyMemQuick(a6)
move.l a2,a1
move.l -(a1),d0
jsr _LVOFreeMem(a6)
jsr _LVOPermit(a6)
move.l a3,d0 ; return()
movem.l (sp)+,d2-d7/a2-a6
rts
RAVFail jsr _LVOPermit(a6)
moveq #0,d0
movem.l (sp)+,d2-d7/a2-a6
rtsLast updated on