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; Zilog eZ80 ANSI C Compiler Release 3.4
; -optsize -nomodsect -peephole -globalopt -localcse
; -const=ROM
FILE "..\MALLOC.C"
.assume ADL=1
SEGMENT BSS
__alloc_base:
DS 6
; 1 /************************************************************************/
; 2 /* */
; 3 /* Copyright (C)1987-2011 by */
; 4 /* Zilog, Inc. */
; 5 /* */
; 6 /* San Jose, California */
; 7 /* */
; 8 /* This implements a straight forward version of malloc, allocating */
; 9 /* memory between the first unused address in RAM (__heapbot) and */
; 10 /* the current stack pointer; the stack pointer being initialized to */
; 11 /* the top of RAM (__heaptop). */
; 12 /* The Zilog real time kernel, RZK, implements an entirely */
; 13 /* different version of malloc. */
; 14 /* */
; 15 /* ZDS arranges that this malloc does not get linked into RZK */
; 16 /* applications by placing the C runtime library, crt.lib or */
; 17 /* crtD.lib, after the RZK libraries in the linker command file. */
; 18 /* */
; 19 /************************************************************************/
; 20 #include <stddef.h>
; 21 #include <stdlib.h>
; 22
; 23 HEADER _alloc_base; /* empty list to get started */
SEGMENT CODE
; 24 extern void *_s_sbrk(size_t);
; 25
; 26 /*************************************************
; 27 *
; 28 * morecore - get more memory for heap
; 29 *
; 30 * Inputs:
; 31 * nu - number of units
; 32 *
; 33 * Returns:
; 34 * the address of the new memory
; 35 *
; 36 *************************************************/
; 37
; 38 static void* morecore(size_t nbytes)
; 39 {
_morecore:
LD HL,-3
CALL __frameset
; 40 register void *cp;
; 41 if(cp = _s_sbrk(nbytes))
LD BC,(IX+6)
PUSH BC
CALL __s_sbrk
POP BC
LD (IX+-3),HL
CALL __icmpzero
JR Z,L_1
; 42 {
; 43 ((HEADER*)cp)->s.size=nbytes;
LD BC,(IX+6)
LD IY,(IX+-3)
LD (IY+3),BC
; 44 cp = ((HEADER*)cp) + 1;
LEA IY,IY+6
LD (IX+-3),IY
; 45 }
L_1:
; 46 return(cp);
LD HL,(IX+-3)
; 47 }
LD SP,IX
POP IX
RET
;**************************** _morecore ***************************
;Name Addr/Register Size Type
;__s_sbrk IMPORT ----- function
;cp IX-3 3 variable
;nbytes IX+6 3 parameter
; Stack Frame Size: 12 (bytes)
; Spill Code: 0 (instruction)
; 48
; 49 /*************************************************
; 50 *
; 51 * malloc - allocate heap storage
; 52 *
; 53 * Inputs:
; 54 * nbytes - number of bytes to allocate
; 55 *
; 56 * Returns:
; 57 * the address of the memory or NULL
; 58 *
; 59 *************************************************/
; 60
; 61 void *malloc(size_t nbytes)
; 62 {
_malloc:
LD HL,-9
CALL __frameset
; 63 HEADER *p,*q;
; 64 size_t size = nbytes + sizeof(HEADER);
LD IY,(IX+6)
LEA IY,IY+6
LD (IX+-6),IY
; 65
; 66 if (size < nbytes)
LD BC,(IX+6)
LD HL,(IX+-6)
OR A,A
SBC HL,BC
JR NC,L_11
OR A,A
; 67 return NULL; // Happens on malloc(-1) or like stupidity
SBC HL,HL
JR L_13
L_11:
; 68
; 69 for(p=&_alloc_base; q=p->s.ptr; p=q)
LD BC,__alloc_base
LD (IX+-9),BC
JR L_10
L_8:
; 70 {
; 71 if (q->s.size >= size)
LD BC,(IX+-6)
LD IY,(IX+-3)
LD HL,(IY+3)
OR A,A
SBC HL,BC
JR C,L_9
; 72 {
; 73 /* big enough */
; 74 if (q->s.size <= size+sizeof(HEADER))
LD IY,(IX+-6)
LEA HL,IY+6
LD IY,(IX+-3)
LD BC,(IY+3)
OR A,A
SBC HL,BC
JR C,L_5
; 75 {
; 76 /* exactly enough */
; 77 p->s.ptr = q->s.ptr;
LD IY,(IX+-3)
LD BC,(IY+0)
LD IY,(IX+-9)
LD (IY+0),BC
; 78 }
; 79 else
JR L_6
L_5:
; 80 {
; 81 q->s.size -= size;
LD IY,(IX+-3)
LD HL,(IY+3)
LD BC,(IX+-6)
OR A,A
SBC HL,BC
LD (IY+3),HL
; 82 q = (HEADER*)(((char*)q) + q->s.size);
LD BC,(IY+3)
LD HL,(IX+-3)
ADD HL,BC
LD (IX+-3),HL
; 83 q->s.size = size;
LD BC,(IX+-6)
LD IY,(IX+-3)
LD (IY+3),BC
; 84 }
L_6:
; 85 return((void*)(q+1));
LD IY,(IX+-3)
LEA HL,IY+6
JR L_13
; 86 }
; 87 }
L_9:
LD BC,(IX+-3)
LD (IX+-9),BC
L_10:
LD IY,(IX+-9)
LD BC,(IY+0)
LD (IX+-3),BC
LD HL,BC
CALL __icmpzero
JR NZ,L_8
; 88 return(morecore(size));
LD BC,(IX+-6)
PUSH BC
CALL _morecore
POP BC
; 89 }
L_13:
LD SP,IX
POP IX
RET
;**************************** _malloc ***************************
;Name Addr/Register Size Type
;__alloc_base STATIC 6 variable
;p IX-9 3 variable
;size IX-6 3 variable
;q IX-3 3 variable
;nbytes IX+6 3 parameter
; Stack Frame Size: 18 (bytes)
; Spill Code: 0 (instruction)
XREF __s_sbrk:ROM
XREF __frameset:ROM
XREF __icmpzero:ROM
XDEF _malloc
XDEF __alloc_base
END
|