131 lines
3.8 KiB
NASM
131 lines
3.8 KiB
NASM
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; File:
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; apisupt.asm
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; Description:
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; Assembly support routines for stack manipulation, etc.
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;
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; Copyright (c) 1995, 1998
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; Pasquale J. Villani
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; All Rights Reserved
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;
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; This file is part of DOS-C.
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;
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; DOS-C is free software; you can redistribute it and/or
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; modify it under the terms of the GNU General Public License
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; as published by the Free Software Foundation; either version
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; 2, or (at your option) any later version.
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;
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; DOS-C is distributed in the hope that it will be useful, but
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; WITHOUT ANY WARRANTY; without even the implied warranty of
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; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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; the GNU General Public License for more details.
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;
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; You should have received a copy of the GNU General Public
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; License along with DOS-C; see the file COPYING. If not,
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; write to the Free Software Foundation, 675 Mass Ave,
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; Cambridge, MA 02139, USA.
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;
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; $Id: apisupt.asm 538 2003-03-12 22:43:53Z bartoldeman $
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;
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%include "segs.inc"
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segment HMA_TEXT
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%if 0
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extern _api_sp:wrt DGROUP ; api stacks - for context
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extern _api_ss:wrt DGROUP ; switching
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extern _usr_sp:wrt DGROUP ; user stacks
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extern _usr_ss:wrt DGROUP
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global _set_stack
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;
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; void set_stack(void) -
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; save current stack and setup our local stack
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;
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_set_stack:
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; save foreground stack
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; we need to get the return values from the stack
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; since the current stack will change
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pop ax ;get return offset
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; Save the flags so that we can restore correct interrupt
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; state later. We need to disable interrupts so that we
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; don't trash memory with new sp-old ss combination
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pushf
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pop dx
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cli
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; save bp
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push bp
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mov cx, sp
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neg cx
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; save away foreground process' stack
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push word [_usr_ss]
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push word [_usr_sp]
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mov word [_usr_ss],ss
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mov word [_usr_sp],sp
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; setup our local stack
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mov ss,word [_api_ss]
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mov sp,word [_api_sp]
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add cx, sp
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add bp, cx
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; setup for ret
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push ax
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; now restore interrupt state
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push dx
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popf
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ret
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;
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; void restore_stack(void) -
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; restore foreground stack, throw ours away
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;
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global _restore_stack
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_restore_stack:
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; we need to get the return values from the stack
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; since the current stack will change
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pop cx ;get return offset
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; Save the flags so that we can restore correct interrupt
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; state later. We need to disable interrupts so that we
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; don't trash memory with new sp-old ss combination
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pushf
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pop dx
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cli
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; save background stack
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mov word [_api_ss],ss
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mov word [_api_sp],sp
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; restore foreground stack here
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mov ss,word [_usr_ss]
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mov sp,word [_usr_sp]
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pop word [_usr_sp]
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pop word [_usr_ss]
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; make bp relative to our stack frame
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pop bp
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;mov bp,sp
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; setup for ret
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push cx
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; now restore interrupt state
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push dx
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popf
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ret
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%endif
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