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1.1 root 1: TITLE stdalloc - memory allocation routine for stdargv, stdenvp
2: ;***
3: ;stdalloc.asm - memory allocation routine for stdargv, stdenvp
4: ;
5: ; Copyright (c) 1985-1987, Microsoft Corporation. All rights reserved.
6: ;
7: ;Purpose:
8: ; Memory allocation for stdargv and stdenvp.
9: ;
10: ;*******************************************************************************
11:
12: include version.inc
13: .xlist
14: ifdef _QC ;[3] Move these includes out of version.inc
15: include \sl\qc\src\include\kernel.inc ;[3]
16: include \sl\qc\src\include\kmac.inc ;[3]
17: endif ;_QC ;[3]
18:
19: include cmacros.inc
20: include msdos.inc
21: include brkctl.inc
22: .list
23:
24:
25: sBegin data
26: assumes ds,data
27: externW _psp ; PSP segment #
28: externW _abrktb ; break table for allocation
29: externW _asizds ; break table for allocation end
30:
31: ifdef _QC ; [1]
32: extrn __QCrtcsip:DWORD ; [1]
33: endif ;_QC ; [1]
34:
35: sEnd data
36:
37: sBegin code
38: assumes ds,data
39: assumes cs,code
40:
41: externNP _amsg_exit ; write error and die routine
42:
43: page
44: ;***
45: ;_myalloc - low overhead heap allocation
46: ;
47: ;Purpose:
48: ; Used to allocate heap space, without the overhead of
49: ; malloc for both wildcard arguments and environment strings, ptrs.
50: ;
51: ; Tries to find space in heap, failing this calls dos to extend
52: ; heap and tries again, failing this spits out error message and
53: ; dies.
54: ;
55: ;Entry:
56: ; BP = number of bytes in table ( argv/ or envp )
57: ; AX = total number of bytes to allocate table and strings
58: ; DI = error message number in case of death.
59: ;
60: ;Exit:
61: ; BP = points to table
62: ; AX = size of table in bytes.
63: ;
64: ;Uses:
65: ;
66: ;Exceptions:
67: ; If can't get enough memory, gives
68: ; error 2009/2008: no space for enviroment/arguments
69: ; and then dies.
70: ;
71: ;*******************************************************************************
72:
73:
74: cProc _myalloc,<NEAR,PUBLIC>,<>
75:
76: cBegin nogen
77: assumes ds,data
78: mov dx,ax ; save size of environment
79: add ax,[_abrktb].sz ; ax = DS offset of end of environment
80: jc _hpovr ; environment won't fit w/in 64k
81: ; give error
82: cmp [_asizds],ax ; will env fit in allocated mem?
83: jnc _hpok ; yes, go move it
84: ; need more memory
85: add ax,15d ; round up to nearest paragraph
86: push ax ; save this for later
87: rcr ax,1 ; shift right including carry from add
88: mov cl,3
89: shr ax,cl ; convert to # of paragraphs
90: mov cx,ds
91: mov bx,[_psp]
92: sub cx,bx ; DGROUP - _PSP
93: add ax,cx ; make # of paragraphs _PSP relative
94: mov es,bx ; seg addr of mem area
95: mov bx,ax ; set up for OS call
96: callos setmem ; change size of mem block to bx paras
97: pop ax ; restore (env size + 15)
98: jc _hpovr ; not enough memory, give error
99: and al,0F0h ; round down to nearest paragraph addr
100: dec ax
101: mov [_asizds],ax ; store new last byte of DGROUP
102:
103: _hpok:
104: xchg ax,bp ; ax = size of env ptr table
105: mov bp,[_abrktb].sz ; bp points to mem for storing env ptrs
106: add [_abrktb].sz,dx ; update bottom of heap
107: ret
108:
109: _hpovr:
110: ifdef _QC ; [1]
111: extrn $F_PSP:WORD ;[2]
112: mov ds,cs:[$F_PSP] ;[2] get PSP
113: mov ax,ds:[PSP_DGROUP_SEG] ;[2] get DGROUP
114: mov ds, ax ;[2] ds = DGROUP
115:
116: pop word ptr [__QCrtcsip] ; [1] Offset
117: mov word ptr [__QCrtcsip+2], cs ; [1] Segment (proc is near)
118: endif ;_QC ; [1]
119:
120: mov ax,di ; error 2009/2008: no space for enviroment/arguments
121: jmp _amsg_exit ; give error and die
122:
123: cEnd nogen
124:
125:
126: sEnd code
127:
128: end
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