/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* reloc.h - assemble for HP-PA */ /* Defines machine specific relocation entries */ #ifndef HPPA_RELOC_INCLUDED #define HPPA_RELOC_INCLUDED /* * Relocation types used in the hppa implementation. Relocation entries for * things other than instructions use the same generic relocation as discribed * in <mach-o/reloc.h> and their r_type is HPPA_RELOC_VANILLA. The rest of the * relocation types are for instructions. Since they are for instructions the * r_address field indicates the 32 bit instruction that the relocation is to * be preformed on. The field r_pcrel is set only for the HPPA_RELOC_BR17. * And r_length is set to long for all non-RELOC_VANILLA r_types. */ enum reloc_type_hppa { HPPA_RELOC_VANILLA, /* generic relocation as discribed in <mach-o/reloc.h>*/ HPPA_RELOC_PAIR, /* the second relocation entry of a pair */ HPPA_RELOC_HI21, /* a PAIR follows with the low part */ HPPA_RELOC_LO14, /* a PAIR follows with the high part */ HPPA_RELOC_BR17, /* 17 bit branch displacement (to a word address) a PAIR follows with the high part */ HPPA_RELOC_BL17, /* a bl instruction (overlow causes an error) */ HPPA_RELOC_JBSR, /* a bl instruction that is targeted at a long branch stub, a PAIR follows with the high part */ HPPA_RELOC_SECTDIFF, /* a PAIR follows with subtract symbol value */ HPPA_RELOC_HI21_SECTDIFF, /* a PAIR follows with subtract symbol value */ HPPA_RELOC_LO14_SECTDIFF, /* a PAIR follows with subtract symbol value */ HPPA_RELOC_PB_LA_PTR /* prebound lazy pointer */ }; /* * For the HI and LO relocation types the two parts of the relocated expression * (symbol + offset) are calculated as follows: * * rounded = round(offset, 0x2000); * left21 = (symbol + rounded) & 0xfffff800; * right14 = ((symbol + rounded) & 0x000007ff) + (offset - rounded); * * This allows the left part to be shared between references with different * offsets as long as the rounded offsets are the same. * * The HPPA_RELOC_BR17 r_type also uses the above calculation and the right14 * bits, sign extened to fill the displacement, and converted to a word * displacement by droping the low bits (after checking they are zero). */ /* * For relocation types that use pairs the part of the relocated expression that * is not stored in the instruction is stored in the r_address feild of the * PAIR's entry. * * All low parts are stored as sign extened byte addressed values in the PAIR's * r_address field as 32 bit values. This allows the HI21 not to have to know * which type of low it is used with. * * The high parts are left justified 21 bit values zero filled to 32 bits and * stored in the PAIR's r_address field. */ /* * The instructions that use the non-RELOC_VANILLA r_types are and the r_types * they use are as follows: * instructions r_type * * LDIL,ADDIL HPPA_RELOC_HI21 * LDx, STx, LDO HPPA_RELOC_LO14 * BE, BLE HPPA_RELOC_BR17 * BL HPPA_RELOC_BL17 * * For the HPPA_RELOC_JBSR the BL instruction must be targeted at a long branch * stub that can be reached with 17 bits of signed word displacement. Also the * stub must be in the same block as the BL instruction so that scattered * loading done by the link editor will not move them apart. For example in * assembly code: * jbsr foo,%r2,L1 ; creates a bl inst with a HPPA_RELOC_JBSR * ; relocation entry for the symbol foo and the * ; instruction is targeted to L1 * ... * L1: ldil L'foo,%r1 ; a HPPA_RELOC_HI21 entry for symbol foo * ble,n R'foo(%sr4,%r1) ; a HPPA_RELOC_BR17 entry for symbol foo */ #endif /* HPPA_RELOC_INCLUDED */