From 1229b3b62303e00693cfb052fca6e4f7879cf0af Mon Sep 17 00:00:00 2001 From: Alec Roelke Date: Wed, 30 Nov 2016 17:10:28 -0500 Subject: riscv: [Patch 3/5] Added RISCV floating point extensions RV64FD Third of five patches adding RISC-V to GEM5. This patch adds the RV64FD extensions, which include single- and double-precision floating point instructions. Patch 1 introduced RISC-V and implemented the base instruction set, RV64I and patch 2 implemented the integer multiply extension, RV64M. Patch 4 will implement the atomic memory instructions, RV64A, and patch 5 will add support for timing, minor, and detailed CPU models that is missing from the first four patches. [Fixed exception handling in floating-point instructions to conform better to IEEE-754 2008 standard and behavior of the Chisel-generated RISC-V simulator.] [Fixed style errors in decoder.isa.] [Fixed some fuzz caused by modifying a previous patch.] Signed-off by: Alec Roelke Signed-off by: Jason Lowe-Power --- src/arch/riscv/isa/formats/formats.isa | 1 + src/arch/riscv/isa/formats/fp.isa | 136 +++++++++++++++++++++++++++++++++ 2 files changed, 137 insertions(+) create mode 100644 src/arch/riscv/isa/formats/fp.isa (limited to 'src/arch/riscv/isa/formats') diff --git a/src/arch/riscv/isa/formats/formats.isa b/src/arch/riscv/isa/formats/formats.isa index b015f8baa..7e4dc6ef0 100644 --- a/src/arch/riscv/isa/formats/formats.isa +++ b/src/arch/riscv/isa/formats/formats.isa @@ -36,6 +36,7 @@ //Include the type formats ##include "type.isa" ##include "mem.isa" +##include "fp.isa" // Include the unknown ##include "unknown.isa" diff --git a/src/arch/riscv/isa/formats/fp.isa b/src/arch/riscv/isa/formats/fp.isa new file mode 100644 index 000000000..97a5a2a50 --- /dev/null +++ b/src/arch/riscv/isa/formats/fp.isa @@ -0,0 +1,136 @@ +// -*- mode:c++ -*- + +// Copyright (c) 2015 Riscv Developers +// Copyright (c) 2016 The University of Virginia +// 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: Alec Roelke + +//////////////////////////////////////////////////////////////////// +// +// Floating point operation instructions +// +def template FloatExecute {{ + Fault %(class_name)s::execute(CPU_EXEC_CONTEXT *xc, + Trace::InstRecord *traceData) const + { + Fault fault = NoFault; + + %(op_decl)s; + %(op_rd)s; + if (fault == NoFault) { + switch (ROUND_MODE) { + case 0x0: + std::fesetround(FE_TONEAREST); + break; + case 0x1: + std::fesetround(FE_TOWARDZERO); + break; + case 0x2: + std::fesetround(FE_DOWNWARD); + break; + case 0x3: + std::fesetround(FE_UPWARD); + break; + case 0x4: + panic("Round to nearest, " + "ties to max magnitude not implemented."); + break; + case 0x7: { + uint8_t frm = xc->readMiscReg(MISCREG_FRM); + switch (frm) { + case 0x0: + std::fesetround(FE_TONEAREST); + break; + case 0x1: + std::fesetround(FE_TOWARDZERO); + break; + case 0x2: + std::fesetround(FE_DOWNWARD); + break; + case 0x3: + std::fesetround(FE_UPWARD); + break; + case 0x4: + panic("Round to nearest," + " ties to max magnitude not implemented."); + break; + default: + fault = std::make_shared(frm); + break; + } + break; + } + default: + fault = std::make_shared(ROUND_MODE); + break; + } + + if (fault == NoFault) { + MiscReg FFLAGS = xc->readMiscReg(MISCREG_FFLAGS); + std::feclearexcept(FE_ALL_EXCEPT); + %(code)s; + if (std::fetestexcept(FE_INEXACT)) { + FFLAGS |= FloatInexact; + } + if (std::fetestexcept(FE_UNDERFLOW)) { + FFLAGS |= FloatUnderflow; + } + if (std::fetestexcept(FE_OVERFLOW)) { + FFLAGS |= FloatOverflow; + } + if (std::fetestexcept(FE_DIVBYZERO)) { + FFLAGS |= FloatDivZero; + } + if (std::fetestexcept(FE_INVALID)) { + FFLAGS |= FloatInvalid; + } + xc->setMiscReg(MISCREG_FFLAGS, FFLAGS); + } + + if (fault == NoFault) { + %(op_wb)s; + } + } + return fault; + } +}}; + +def format FPROp(code, *opt_flags) {{ + iop = InstObjParams(name, Name, 'ROp', code, opt_flags) + header_output = BasicDeclare.subst(iop) + decoder_output = BasicConstructor.subst(iop) + decode_block = BasicDecode.subst(iop) + exec_output = FloatExecute.subst(iop) +}}; + +def format FPR4Op(code, *opt_flags) {{ + iop = InstObjParams(name, Name, 'ROp', code, opt_flags) + header_output = BasicDeclare.subst(iop) + decoder_output = BasicConstructor.subst(iop) + decode_block = BasicDecode.subst(iop) + exec_output = FloatExecute.subst(iop) +}}; -- cgit v1.2.3