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cc65/libsrc/common/_heapblocksize.s
cuz 8eb898d0d1 Adjust result to user visible size
git-svn-id: svn://svn.cc65.org/cc65/trunk@3159 b7a2c559-68d2-44c3-8de9-860c34a00d81
2004-07-17 12:18:51 +00:00

52 lines
938 B
ArmAsm

;
; Ullrich von Bassewitz, 2004-07-17
;
; size_t __fastcall__ _heapblocksize (const void* ptr);
;
; Return the size of an allocated block.
;
.importzp ptr1
.export __heapblocksize
.include "_heap.inc"
.macpack generic
.macpack cpu
;-----------------------------------------------------------------------------
; Code
__heapblocksize:
; Decrement the block pointer so it points to the admin data
sub #HEAP_ADMIN_SPACE ; Assume it's less than 256
bcs L1
dex
L1: sta ptr1
stx ptr1+1
; Load the size from the given block
ldy #1
lda (ptr1),y
tax
.if (.cpu .bitand CPU_ISET_65SC02)
lda (ptr1)
.else
dey
lda (ptr1),y
.endif
; Adjust it to the user visible size
sub #HEAP_ADMIN_SPACE
bcs L9
dex
; Done
L9: rts