From ba7a7b0394d90dd369c65f1ac0869e0ae3f4b644 Mon Sep 17 00:00:00 2001 From: Gabe Black Date: Wed, 2 Jun 2010 12:58:17 -0500 Subject: ARM: Move some predecoder stuff into a .cc file. --HG-- rename : src/arch/arm/predecoder.hh => src/arch/arm/predecoder.cc --- src/arch/arm/predecoder.cc | 164 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 src/arch/arm/predecoder.cc (limited to 'src/arch/arm/predecoder.cc') diff --git a/src/arch/arm/predecoder.cc b/src/arch/arm/predecoder.cc new file mode 100644 index 000000000..20c7058b0 --- /dev/null +++ b/src/arch/arm/predecoder.cc @@ -0,0 +1,164 @@ +/* + * Copyright (c) 2010 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Copyright (c) 2006 The Regents of The University of Michigan + * Copyright (c) 2007-2008 The Florida State University + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Gabe Black + */ + +#include "arch/arm/isa_traits.hh" +#include "arch/arm/predecoder.hh" +#include "base/trace.hh" +#include "cpu/thread_context.hh" + +namespace ArmISA +{ + +void +Predecoder::advanceThumbCond() +{ + uint8_t condMask = itstate.mask; + uint8_t thumbCond = itstate.cond; + DPRINTF(Predecoder, "Advancing ITSTATE from %#x, %#x.\n", + thumbCond, condMask); + condMask = condMask << 1; + uint8_t newBit = bits(condMask, 4); + condMask &= mask(4); + if (condMask == 0) { + thumbCond = 0; + } else { + replaceBits(thumbCond, 0, newBit); + } + DPRINTF(Predecoder, "Advancing ITSTATE to %#x, %#x.\n", + thumbCond, condMask); + itstate.mask = condMask; + itstate.cond = thumbCond; +} + +void +Predecoder::process() +{ + if (!emi.thumb) { + emi.instBits = data; + emi.sevenAndFour = bits(data, 7) && bits(data, 4); + emi.isMisc = (bits(data, 24, 23) == 0x2 && + bits(data, 20) == 0); + DPRINTF(Predecoder, "Arm inst: %#x.\n", (uint64_t)emi); + } else { + uint16_t word = (data >> (offset * 8)); + if (bigThumb) { + // A 32 bit thumb inst is half collected. + emi.instBits = emi.instBits | word; + bigThumb = false; + offset += 2; + DPRINTF(Predecoder, "Second half of 32 bit Thumb: %#x.\n", + emi.instBits); + if (itstate.mask) { + emi.itstate = itstate; + advanceThumbCond(); + emi.newItstate = itstate; + } + } else { + uint16_t highBits = word & 0xF800; + if (highBits == 0xE800 || highBits == 0xF000 || + highBits == 0xF800) { + // The start of a 32 bit thumb inst. + emi.bigThumb = 1; + if (offset == 0) { + // We've got the whole thing. + emi.instBits = (data >> 16) | (data << 16); + DPRINTF(Predecoder, "All of 32 bit Thumb: %#x.\n", + emi.instBits); + offset += 4; + if (itstate.mask) { + emi.itstate = itstate; + advanceThumbCond(); + emi.newItstate = itstate; + } + } else { + // We only have the first half word. + DPRINTF(Predecoder, + "First half of 32 bit Thumb.\n"); + emi.instBits = (uint32_t)word << 16; + bigThumb = true; + offset += 2; + } + } else { + // A 16 bit thumb inst. + offset += 2; + emi.instBits = word; + // Set the condition code field artificially. + emi.condCode = COND_UC; + DPRINTF(Predecoder, "16 bit Thumb: %#x.\n", + emi.instBits); + if (bits(word, 15, 8) == 0xbf && + bits(word, 3, 0) != 0x0) { + emi.itstate = itstate; + itstate = bits(word, 7, 0); + emi.newItstate = itstate; + DPRINTF(Predecoder, + "IT detected, cond = %#x, mask = %#x\n", + itstate.cond, itstate.mask); + } else if (itstate.mask) { + emi.itstate = itstate; + advanceThumbCond(); + emi.newItstate = itstate; + } + } + } + } +} + +//Use this to give data to the predecoder. This should be used +//when there is control flow. +void +Predecoder::moreBytes(Addr pc, Addr fetchPC, MachInst inst) +{ + data = inst; + offset = (fetchPC >= pc) ? 0 : pc - fetchPC; + emi.thumb = (pc & (ULL(1) << PcTBitShift)) ? 1 : 0; + FPSCR fpscr = tc->readMiscReg(MISCREG_FPSCR); + emi.fpscrLen = fpscr.len; + emi.fpscrStride = fpscr.stride; + CPSR cpsr = tc->readMiscReg(MISCREG_CPSR); + itstate.top6 = cpsr.it2; + itstate.bottom2 = cpsr.it1; + process(); +} + +} -- cgit v1.2.3