diff options
Diffstat (limited to 'libc/bcc/heap.c')
| -rw-r--r-- | libc/bcc/heap.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/libc/bcc/heap.c b/libc/bcc/heap.c new file mode 100644 index 0000000..c5b2457 --- /dev/null +++ b/libc/bcc/heap.c @@ -0,0 +1,184 @@ +/* Copyright (C) 1995,1996 Robert de Bath <rdebath@cix.compulink.co.uk> + * This file is part of the Linux-8086 C library and is distributed + * under the GNU Library General Public License. + */ + +#include <errno.h> + +/****************************************************************************/ + +#ifdef L_errno +int errno = 0; /* libc error value */ +#endif + +/****************************************************************************/ + +#ifdef __AS386_16__ + +#ifdef L___brk_addr +#asm +.data +export brk_addr +brk_addr: .word __end ! This holds the current return for sbrk(0) +.text +#endasm +#endif + +/****************************************************************************/ + +#ifdef L_sbrk +int sbrk(brk_off) +int brk_off; +{ +#asm + mov bx,sp +#if !__FIRST_ARG_IN_AX__ + mov ax,[bx+2] ! Fetch the requested value +#endif + test ax,ax + jnz has_change + mov ax,[brk_addr] ! Simple one, read current - can`t fail. + jmp eof + +has_change: + js go_down + add ax,[brk_addr] ! Goin up! + jc Enomem + sub bx,#511 ! Safety space 512 bytes + cmp bx,ax ! Too close ? + jb Enomem + +sbrk_ok: +#if !defined(__MSDOS__) && !defined(__STANDALONE__) + push ax ! MSDOS `kernel` doesn`t care + call ___brk ! Tell the kernel + test ax,ax + pop ax ! ASSUME ___brk doesn`t alter stack! + jnz Enomem ! Ugh! kernel didn`t like the idea! +#endif + xchg [brk_addr],ax ! Save away new val + jmp eof ! Return it +go_down: + add ax,[brk_addr] + jnc Enomem + cmp ax,#__end + jae sbrk_ok + +Enomem: + mov ax,#12 ! This should be ENOMEM not a magic. + mov [_errno],ax + mov ax,#-1 +eof: +#endasm +} +#endif + +/****************************************************************************/ + +#ifdef L_brk +int +brk(new_brk) +char * new_brk; +{ +#asm + mov bx,sp +#if !__FIRST_ARG_IN_AX__ + mov ax,[bx+2] ! Fetch the requested value +#endif + sub bx,#512 ! Safety space 512 bytes + cmp bx,ax ! Too close ? + jb Enomem + cmp ax,#__end + jae brk_ok +Enomem: + mov ax,#12 ! This should be ENOMEM not a magic. + mov [_errno],ax + mov ax,#-1 + ret +brk_ok: +#if !defined(__MSDOS__) && !defined(__STANDALONE__) + push ax + call ___brk ! Tell the kernel + test ax,ax + pop bx ! ASSUME ___brk doesn`t alter stack! + jnz Enomem ! Ugh! kernel didn`t like the idea! + mov [brk_addr],bx ! Save away new val +#else + mov [brk_addr],ax ! MSDOS `kernel` doesn`t care + mov ax,#0 +#endif +#endasm +} +#endif + +#endif + +/****************************************************************************/ + +#ifdef __AS386_32__ +extern char * __brk_addr; +extern char * __brk(); + +#ifdef L___brk_addr +char * __brk_addr = 0; /* This holds the current return for sbrk(0) */ + +char * +__brk(val) +{ +#asm +#if __FIRST_ARG_IN_AX__ + mov ebx,eax +#else + mov ebx,[esp+4] +#endif + mov eax,#45 + int $80 +#endasm +} + +__brk_addr_init() +{ + if( __brk_addr == 0 && (__brk_addr = __brk(0)) == 0 ) + { + errno = ENOMEM; + return -1; + } + return 0; +} +#endif + +#ifdef L_sbrk +char * +sbrk(brk_off) +int brk_off; +{ + char * new_brk; + if( __brk_addr_init() ) return (char*)-1; + if( brk_off == 0 ) return __brk_addr; + + new_brk = __brk_addr + brk_off; + __brk_addr = __brk(new_brk); + if( __brk_addr != new_brk ) + { + errno = ENOMEM; + return (char*)-1; + } + return __brk_addr - brk_off; +} +#endif + +#ifdef L_brk +int +brk(new_brk) +char * new_brk; +{ + if( __brk_addr_init() ) return -1; + + __brk_addr = __brk(new_brk); + if( __brk_addr == new_brk ) return 0; + errno = ENOMEM; + return -1; +} +#endif + +#endif |