/* * (C) Copyright 2001 * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <asm/ppc4xx.h> /***************************************************************************** * * XXX - DANGER * These routines make use of self modifying code. DO NOT CALL THEM * UNTIL THEY ARE RELOCATED TO RAM. Additionally, I do not * recommend them for use in anything other than an interactive * debugging environment. This is mainly due to performance reasons. * ****************************************************************************/ /* * static void _create_MFDCR(unsigned short dcrn) * * Builds a 'mfdcr' instruction for get_dcr * function. */ .section ".text" .align 2 .type _create_MFDCR,@function _create_MFDCR: /* * Build up a 'mfdcr' instruction formatted as follows: * * OPCD | RT | DCRF | XO | CR | * ---------------|--------------|--------------|----| * 0 5 | 6 10 | 11 20 | 21 30 | 31 | * | | DCRN | | | * 31 | %r3 | (5..9|0..4) | 323 | 0 | * * Where: * OPCD = opcode - 31 * RT = destination register - %r3 return register * DCRF = DCRN # with upper and lower halves swapped * XO = extended opcode - 323 * CR = CR[CR0] NOT undefined - 0 */ rlwinm r0, r3, 27, 27, 31 /* OPCD = 31 */ rlwinm r3, r3, 5, 22, 26 or r3, r3, r0 slwi r3, r3, 10 oris r3, r3, 0x3e30 /* RT = %r3 */ ori r3, r3, 323 /* XO = 323 */ slwi r3, r3, 1 /* CR = 0 */ mflr r4 stw r3, 0(r4) /* Store instr in get_dcr() */ dcbst r0, r4 /* Make sure val is written out */ sync /* Wait for write to complete */ icbi r0, r4 /* Make sure old instr is dumped */ isync /* Wait for icbi to complete */ blr .Lfe1: .size _create_MFDCR,.Lfe1-_create_MFDCR /* end _create_MFDCR() */ /* * static void _create_MTDCR(unsigned short dcrn, unsigned long value) * * Builds a 'mtdcr' instruction for set_dcr * function. */ .section ".text" .align 2 .type _create_MTDCR,@function _create_MTDCR: /* * Build up a 'mtdcr' instruction formatted as follows: * * OPCD | RS | DCRF | XO | CR | * ---------------|--------------|--------------|----| * 0 5 | 6 10 | 11 20 | 21 30 | 31 | * | | DCRN | | | * 31 | %r3 | (5..9|0..4) | 451 | 0 | * * Where: * OPCD = opcode - 31 * RS = source register - %r4 * DCRF = dest. DCRN # with upper and lower halves swapped * XO = extended opcode - 451 * CR = CR[CR0] NOT undefined - 0 */ rlwinm r0, r3, 27, 27, 31 /* OPCD = 31 */ rlwinm r3, r3, 5, 22, 26 or r3, r3, r0 slwi r3, r3, 10 oris r3, r3, 0x3e40 /* RS = %r4 */ ori r3, r3, 451 /* XO = 451 */ slwi r3, r3, 1 /* CR = 0 */ mflr r5 stw r3, 0(r5) /* Store instr in set_dcr() */ dcbst r0, r5 /* Make sure val is written out */ sync /* Wait for write to complete */ icbi r0, r5 /* Make sure old instr is dumped */ isync /* Wait for icbi to complete */ blr .Lfe2: .size _create_MTDCR,.Lfe2-_create_MTDCR /* end _create_MTDCR() */ /* * unsigned long get_dcr(unsigned short dcrn) * * Return a given DCR's value. */ /* */ /* XXX - This is self modifying code, hence */ /* it is in the data section. */ /* */ .section ".text" .align 2 .globl get_dcr .type get_dcr,@function get_dcr: mflr r0 /* Get link register */ stwu r1, -32(r1) /* Save back chain and move SP */ stw r0, +36(r1) /* Save link register */ bl _create_MFDCR /* Build following instruction */ /* XXX - we build this instuction up on the fly. */ .long 0 /* Get DCR's value */ lwz r0, +36(r1) /* Get saved link register */ mtlr r0 /* Restore link register */ addi r1, r1, +32 /* Remove frame from stack */ blr /* Return to calling function */ .Lfe3: .size get_dcr,.Lfe3-get_dcr /* end get_dcr() */ /* * unsigned void set_dcr(unsigned short dcrn, unsigned long value) * * Return a given DCR's value. */ /* * XXX - This is self modifying code, hence * it is in the data section. */ .section ".text" .align 2 .globl set_dcr .type set_dcr,@function set_dcr: mflr r0 /* Get link register */ stwu r1, -32(r1) /* Save back chain and move SP */ stw r0, +36(r1) /* Save link register */ bl _create_MTDCR /* Build following instruction */ /* XXX - we build this instuction up on the fly. */ .long 0 /* Set DCR's value */ lwz r0, +36(r1) /* Get saved link register */ mtlr r0 /* Restore link register */ addi r1, r1, +32 /* Remove frame from stack */ blr /* Return to calling function */ .Lfe4: .size set_dcr,.Lfe4-set_dcr /* end set_dcr() */