ibmstack.c

gameboy游戏模拟器,COMMON.H CONV.C DASM.C DEBUG.C FILE_ID.DIZ FMFREQS.C FMFREQS.H GB.C GB.H GBLIST.C HEL

/* IbmStack.c
   This file is part of the VGB-DOS project
   Copyright (C) Marcel de Kogel ([e-mail]), 1996
   You may not use this file for commercial purposes
   Please notify me if you make any changes to this file */

/* #define TEST */

#include "GB.h"
#include "IbmMsdos.h"

#include <stdlib.h>
#include <dos.h>
#include <go32.h>
#include <dpmi.h>
#include <stdio.h>

#define MIN_STACK_SIZE          1024
#define MAX_STACK_SIZE          65536
#define MIN_STACK_NR            4
#define MAX_STACK_NR            64

static unsigned **StackPtr;
static int StackSize;
static int NumStacks;
static int NumStacksUsed;
static int NumFailed;

static int TotalFailed=0;
static int TotalSuccess=0;
static int MaxStacksUsed=0;

void ExitStacks (void)
{
 int i;
 if (!StackPtr)
  return;
 for (i=0;i<NumStacks;++i)
  if (StackPtr[i])
   free (StackPtr[i]);
  else
   break;
 free (StackPtr);
 StackPtr=0;
#ifdef TEST
 printf ("\n%d,%d,%d\n",TotalFailed,TotalSuccess,MaxStacksUsed);
#endif
}

int InitStacks (int nr,int size)
{
 int i;
 if (StackPtr)
  return 1;                     /* allready called */
 if (size<MIN_STACK_SIZE)
  size=MIN_STACK_SIZE;
 if (size>MAX_STACK_SIZE)
  size=MAX_STACK_SIZE;
 if (nr<MIN_STACK_NR)
  nr=MIN_STACK_NR;
 if (nr>MAX_STACK_NR)
  nr=MAX_STACK_NR;
 if (size&3)
  size=(size&(~3))+4;           /* stack must be dword-aligned */
 StackPtr=malloc (nr*4);
 if (!StackPtr)
  return 0;
 StackSize=size;
 NumStacks=nr;
 for (i=0;i<nr;++i)
 {
  StackPtr[i]=malloc(size);
  if (!StackPtr[i])
  {
   ExitStacks ();
   return 0;
  }
 }
 NumStacksUsed=0;
 NumFailed=0;
 return 1;
}

/* AllocStack return cf=1 when no stack could be allocated.
   FreeStack() must be wether a stack could be allocated or not */
asm ("
.globl _AllocStack
_AllocStack:
 popl   %esi
 movl   _NumStacksUsed,%eax
 cmpl   _NumStacks,%eax
 jae    AllocStack_Failed
 incl   %eax
 movl   %eax,_NumStacksUsed
 cmpl   _MaxStacksUsed,%eax
 jbe    Alloc_1
 movl   %eax,_MaxStacksUsed
Alloc_1:
 incl   _TotalSuccess
 movl   _StackPtr,%ebx
 decl   %eax
 leal   (%ebx,%eax,4),%ebx
 movl   (%ebx),%ebx
 addl   _StackSize,%ebx
 subl   $64,%ebx
 movw   %ss,%cx
 movl   %esp,%edx
 movw   %ds,%ax
 movw   %ax,%ss
 movl   %ebx,%esp
 pushl  %edx
 pushw  %cx
 clc
 jmpl   %esi
AllocStack_Failed:
 incl   _NumFailed
 incl   _TotalFailed
 stc
 jmpl   %esi

.globl _FreeStack
_FreeStack:
 popl   %esi
 cmpl   $0,_NumFailed
 jne    FreeStack_Failed
 popw   %ax
 popl   %edx
 movw   %ax,%ss
 movl   %edx,%esp
 decl   _NumStacksUsed
 jmpl   %esi
FreeStack_Failed:
 decl   _NumFailed
 jmpl   %esi
");