ppcenc2.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 94 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
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*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


#include "standard.h"
#include "coderep.h"
#include "opcodes.h"
#include "pattern.h"
#include "ocentry.h"
#include "ppcenc.h"
#include "reloc.h"
#include "offset.h"
#include "optopts.h"
#include "optlbl.h"

extern void ObjBytes( const char *, unsigned );
extern void OutReloc( pointer, owl_reloc_type, unsigned );

void EncodeRet( oc_ret *oc ) {

    ppc_ins             encoding;

    oc = oc;
    encoding = 0x6bfa8001;      // this is a little cheesy - ret ra(r26)
    ObjBytes( (char *)&encoding, sizeof( encoding ) );
}

static void doBranch( ppc_ins opcode, pointer lbl, uint reg ) {

    opcode = 0; // _Opcode( opcode ) | _A( reg );
    OutReloc( lbl, OWL_RELOC_BRANCH_REL, 0 );
    ObjBytes( (char *)&opcode, sizeof( opcode ) );
}

void EncodeJump( oc_handle *oc ) {

    doBranch( 0x30, oc->handle, 0 );
}

void EncodeCall( oc_handle *oc ) {

    doBranch( 0x34, oc->handle, 0 );
}

static  uint_8  BranchOpcodes[][2] = {
    { 0x39, 0x31 },                     /* OP_CMP_EQUAL */
    { 0x3d, 0x35 },                     /* OP_CMP_NOT_EQUAL */
    { 0x3f, 0x37 },                     /* OP_CMP_GREATER */
    { 0x3b, 0x33 },                     /* OP_CMP_LESS_EQUAL */
    { 0x3a, 0x32 },                     /* OP_CMP_LESS */
    { 0x3e, 0x36 },                     /* OP_CMP_GREATER_EQUAL */
};

void EncodeCond( oc_jcond *oc ) {

    ppc_ins     opcode;
    int         floating;

    floating = 0;
    if( oc->op.class & ATTR_FLOAT ) {
        floating = 1;
    }
    opcode = BranchOpcodes[ oc->cond - FIRST_COMPARISON ][ floating  ];
    doBranch( opcode, oc->handle, oc->index );
}