386rtrtn.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 478 行 · 第 1/2 页

        byte_seq_len    length;
        char            data[];
} rt_aux_info;

static  rt_aux_info Scn1 = {
                        0, 2,
                       {0xF2,                   /*       repne     */
                        0xAE}                   /*       scasb     */
                        };

static  rt_aux_info Scn1ES = {
                        0, 6,
                       {0x06,                   /*      push    es */
                        0x0e,                   /*      push    cs */
                        0x07,                   /*      pop     es */
                        0xF2,                   /*      repne      */
                        0xAE,                   /*      scasb      */
                        0x07}                   /*      pop     es */
                        };

static  rt_aux_info Scn2 = {            /* or Scn4 in USE16 */
                        0, 3,
                       {0xF2,                   /*       repne     */
                        0x66, 0xAF}             /*       scasw     */
                        };

static  rt_aux_info Scn2ES = {          /* or Scn4 in USE16 */
                        0, 7,
                       {0x06,                   /*      push    es */
                        0x0e,                   /*      push    cs */
                        0x07,                   /*      pop     es */
                        0xF2,                   /*      repne      */
                        0x66, 0xAF,             /*      scasw      */
                        0x07}                   /*      pop     es */
                        };

static  rt_aux_info Scn4 = {            /* or Scn2 in USE16 */
                        0, 2,
                       {0xF2,                   /*       repne     */
                        0xAF}                   /*       scasd     */
                        };

static  rt_aux_info Scn4ES = {          /* or Scn2 in USE16 */
                        0, 6,
                       {0x06,                   /*      push    es */
                        0x0e,                   /*      push    cs */
                        0x07,                   /*      pop     es */
                        0xF2,                   /*      repne      */
                        0xAF,                   /*      scasd      */
                        0x07}                   /*      pop     es */
                        };
#include "cgrealgn.h"


extern  char    *AskRTName( int rtindex )
/***************************************/
{
    if( _IsTargetModel( INDEXED_GLOBALS ) ) {
        switch( rtindex + BEG_RTNS ) {
        case RT_FDA:
            return( "__FXA" );
        case RT_FDS:
            return( "__FXS" );
        case RT_FDM:
            return( "__FXM" );
        case RT_FDD:
            return( "__FXD" );
        case RT_FDC:
            return( "__FXC" );
        case RT_DPOW:
            return( "RT@XPOW" );
        case RT_DATAN2:
            return( "IF@XATAN2" );
        case RT_DFMOD:
            return( "IF@XFMOD" );
        }
    }
    return( RTInfo[  rtindex  ].nam );
}


extern  bool    RTLeaveOp2( instruction *ins )
/*********************************************
    return true if it's a bad idea to put op2 into a temporary since we're
    gonna take the bugger's address in rMAKECALL.
*/
{
    ins = ins;
    return( FALSE );
}


extern  name    *ScanCall( tbl_control *table, name *value,
                           type_class_def tipe )
/**********************************************************
    generates a fake call to a rutime routine that looks up "value" in a table
    and jumps to the appropriate case, using either a pointer or index
    returned by the "routine". The "routine" will be generated inline later.
    See BEAuxInfo for the code sequences generated. That will explain
    how the jump destination is determined as well.
*/
{
    instruction *new_ins;
    name        *reg_name;
    name        *result;
    name        *label;
    hw_reg_set  tmp;

    switch( tipe ) {
    case U1:
        RoutineNum = RT_SCAN1 - BEG_RTNS;
        break;
    case U2:
        RoutineNum = RT_SCAN2 - BEG_RTNS;
        break;
    case U4:
        RoutineNum = RT_SCAN4 - BEG_RTNS;
        break;
    }

    reg_name = AllocRegName( FirstReg( RTInfo[  RoutineNum  ].left ) );
    new_ins = MakeConvert( value, reg_name, tipe, value->n.name_class );
    AddIns( new_ins );

    reg_name = AllocRegName( HW_ECX );
    new_ins = MakeMove( AllocIntConst( table->size + 1 ), reg_name, U4 );
    AddIns( new_ins );

    reg_name = AllocRegName( HW_EDI );
    label = AllocMemory( table, 0, CG_VTB, U4 );
    label = AddrConst( label, AskBackSeg(), CONS_OFFSET );
    new_ins = MakeMove( label, reg_name, U4 );
    AddIns( new_ins );

    new_ins = NewIns( 3 );
    new_ins->head.opcode = OP_CALL;
    new_ins->type_class = U2;
    tmp = FirstReg( RTInfo[ RoutineNum ].left );
    HW_CTurnOn( tmp, HW_ECX );
    HW_CTurnOn( tmp, HW_EDI );
    HW_CTurnOn( tmp, HW_ES );
    new_ins->operands[ CALL_OP_USED ] = AllocRegName( tmp );
    new_ins->operands[ CALL_OP_USED2 ] = new_ins->operands[ CALL_OP_USED ];
    new_ins->operands[ CALL_OP_ADDR ] = AllocMemory( RTLabel(RoutineNum),
                                             0, CG_LBL, U4 );
    new_ins->result = NULL;
    new_ins->num_operands = 2;
    AddIns( new_ins );

    result = AllocMemory( table, 0, CG_TBL, U4 ); /* so table gets freed!*/
    if( tipe == U4 ) {
        HW_CAsgn( tmp, HW_ECX );
        HW_CTurnOn( tmp, HW_EDI );
        new_ins->zap = &AllocRegName( tmp )->r;
        new_ins->result = AllocRegName( HW_EDI );
        HW_CAsgn( tmp, HW_CS );
        HW_CTurnOn( tmp, HW_EDI );
        result = AllocRegName( tmp );
        result = AllocIndex( result, NULL, ( table->size - 1 )*4, U4 );
        new_ins = MakeMove( result, AllocTemp( WD ), WD );
        AddIns( new_ins );
        result = new_ins->result;
    } else {
        HW_CAsgn( tmp, HW_ECX );
        HW_CTurnOn( tmp, HW_EDI );
        new_ins->zap = &AllocRegName( tmp )->r;
        new_ins->result = AllocRegName( HW_ECX );
        new_ins = MakeMove( new_ins->result, AllocTemp( WD ), WD );
        AddIns( new_ins );
        result = AllocIndex( new_ins->result, result, 0, U4 );
        result->i.scale = 2; /* 2**2 == 4 */
    }
    return( result );
}


extern  name    *Addressable( name *cons, type_class_def class )
/***************************************************************
    make sure a floating point constant is addressable (dropped
    it into memory if it isnt)
*/
{
    if( cons->n.class == N_CONSTANT ) return( GenFloat( cons, class ) );
    return( cons );
}


extern  pointer BEAuxInfo( pointer hdl, aux_class request )
/**********************************************************
    see ScanCall for explanation
*/
{
    pointer     info;

    switch( request ) {
    case AUX_LOOKUP:
        switch( FindRTLabel( hdl ) ) {
        case RT_SCAN1:
            if( _IsntTargetModel( FLAT_MODEL ) ) return( &Scn1ES );
            return( &Scn1 );
        case RT_SCAN2:
            if( _IsntTargetModel( USE_32 ) ) {
                if( _IsntTargetModel( FLAT_MODEL ) ) return( &Scn4ES );
                return( &Scn4 );
            } else {
                if( _IsntTargetModel( FLAT_MODEL ) ) return( &Scn2ES );
                return( &Scn2 );
            }
        case RT_SCAN4:
            if( _IsntTargetModel( USE_32 ) ) {
                if( _IsntTargetModel( FLAT_MODEL ) ) return( &Scn2ES );
                return( &Scn2 );
            } else {
                if( _IsntTargetModel( FLAT_MODEL ) ) return( &Scn4ES );
                return( &Scn4 );
            }
        default:
            return( NULL );
        }
    case CALL_CLASS:
        info = hdl;
        return( &((rt_aux_info *)info)->class );
    case CALL_BYTES:
        info = hdl;
        return( &((rt_aux_info *)info)->length );
    default:
        _Zoiks( ZOIKS_128 );
        return( NULL );
    }
}

extern  instruction     *rMAKEFNEG( instruction *ins )
/*****************************************************
    this is intentionally a stub for the 386.
*/
{
    return( ins );
}