intarith.c

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*                            Open Watcom Project
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//
// INTARITH     : integer arithmetic
//

#include "ftnstd.h"
#include "xfflags.h"

extern  bool    __Add( intstar4 *arg1, intstar4 *arg2 );
extern  bool    __Sub( intstar4 *arg1, intstar4 *arg2 );
#ifdef __386__
 #pragma aux    __Add = \
                "mov    edx,[edx]" \
                "add    [eax],edx" \
                "seto   al"        \
                parm [eax] [edx] value [al];
 #pragma aux    __Sub = \
                "mov    edx,[edx]" \
                "sub    [eax],edx" \
                "seto   al"        \
                parm [eax] [edx] value [al];
 extern bool    __Mul( intstar4 *arg1, intstar4 *arg2 );
 #pragma aux    __Mul = \
                "push   ebx"       \
                "mov    edx,[edx]" \
                "mov    ebx,[eax]" \
                "imul   ebx,edx"   \
                "mov    [eax],ebx" \
                "pop    ebx"       \
                "seto   al"        \
                parm [eax] [edx] value [al];
#elif defined( M_I86 )  // 16-bit
 #if defined(__SMALL__) || defined(__MEDIUM__)
  #pragma aux   __Add = \
                "mov    ax,[bx]"   \
                "add    [di],ax"   \
                "mov    ax,2[bx]"  \
                "adc    2[di],ax"  \
                "mov    al,0"      \
                "jno    short L1"  \
                "inc    al"        \
                "L1:"              \
                parm [di] [bx] value [al];
  #pragma aux   __Sub = \
                "mov    ax,[bx]"   \
                "sub    [di],ax"   \
                "mov    ax,2[bx]"  \
                "sbb    2[di],ax"  \
                "mov    al,0"      \
                "jno    short L1"  \
                "inc    al"        \
                "L1:"              \
                parm [di] [bx] value [al];
 #else  // large data models
  #pragma aux   __Add = \
                "push   ds"        \
                "mov    ds,cx"     \
                "push   ax"        \
                "mov    ax,[bx]"   \
                "mov    cx,2[bx]"  \
                "mov    ds,dx"     \
                "pop    bx"        \
                "add    [bx],ax"   \
                "adc    2[bx],cx"  \
                "mov    al,0"      \
                "jno    short L1"  \
                "inc    al"        \
                "L1:pop ds"        \
                parm [dx ax] [cx bx] value [al];
  #pragma aux   __Sub = \
                "push   ds"        \
                "mov    ds,cx"     \
                "push   ax"        \
                "mov    ax,[bx]"   \
                "mov    cx,2[bx]"  \
                "mov    ds,dx"     \
                "pop    bx"        \
                "sub    [bx],ax"   \
                "sbb    2[bx],cx"  \
                "mov    al,0"      \
                "jno    short L1"  \
                "inc    al"        \
                "L1:pop ds"        \
                parm [dx ax] [cx bx] value [al];
 #endif
 extern  bool   ChkI4Mul(intstar4 __far *arg1,intstar4 arg2);
#else
 extern bool    __Mul( intstar4 *arg1, intstar4 *arg2 );
#endif

bool    AddIOFlo( intstar4 *arg1, intstar4 *arg2 ) {
//==================================================

// Add two integers and check for overflow.
#if 0
    __XcptFlags &= ~XF_IOVERFLOW;
    *arg1 += *arg2;
    ChkOverFlow();
    return( ( __XcptFlags & XF_IOVERFLOW ) != 0 );
#else
    return( __Add( arg1, arg2 ) );
#endif
}


bool    SubIOFlo( intstar4 *arg1, intstar4 *arg2 ) {
//==================================================

// Subtract two integers and check for overflow.
#if 0
    __XcptFlags &= ~XF_IOVERFLOW;
    *arg1 -= *arg2;
    ChkOverFlow();
    return( ( __XcptFlags & XF_IOVERFLOW ) != 0 );
#else
    return( __Sub( arg1, arg2 ) );
#endif
}


bool    MulIOFlo( intstar4 *arg1, intstar4 *arg2 ) {
//==================================================

// Multiply two integers and check for overflow.
#if 0
    __XcptFlags &= ~XF_IOVERFLOW;
  #ifdef M_I86
    *arg1 = ChkI4Mul( *arg1, *arg2 );
  #else
    *arg1 *= *arg2;
    ChkOverFlow();
  #endif
    return( ( __XcptFlags & XF_IOVERFLOW ) != 0 );
#else
  #ifdef M_I86
    return( ChkI4Mul( arg1, *arg2 ) );
  #else
    return( __Mul( arg1, arg2 ) );
  #endif
#endif
}