xref: /gem5/src/arch/power/isa/formats/fp.isa

// -*- mode:c++ -*-

// Copyright (c) 2009 The University of Edinburgh
// 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
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Authors: Timothy M. Jones

////////////////////////////////////////////////////////////////////
//
// Floating Point operate instructions
//


let {{

    readFPSCRCode = 'Fpscr fpscr = FPSCR;'

    computeCR1Code = '''
        Cr cr = CR;
        cr.cr1 = (fpscr.fx << 3) | (fpscr.fex << 2) |
                 (fpscr.vx << 1) | fpscr.ox;
        CR = cr;
    '''

}};

// Primary format for floating point operate instructions:
def format FloatOp(code, inst_flags = []) {{
    iop = InstObjParams(name, Name, 'FloatOp',
                        {"code": code},
                        inst_flags)
    header_output = BasicDeclare.subst(iop)
    decoder_output = BasicConstructor.subst(iop)
    decode_block = BasicDecode.subst(iop)
    exec_output = BasicExecute.subst(iop)
}};

// Floating point operations that compute the CR1 code if RC is set. No other
// special registers are touched using these operations.
def format FloatRCCheckOp(code, inst_flags = []) {{

    # Code when Rc is set
    code_rc1 = code + readFPSCRCode + computeCR1Code

    # Generate the first class
    (header_output, decoder_output, decode_block, exec_output) = \
        GenAluOp(name, Name, 'FloatOp', code, inst_flags,
                 CheckRcDecode, BasicConstructor)

    # Generate the second class
    (header_output_rc1, decoder_output_rc1, _, exec_output_rc1) = \
        GenAluOp(name, Name + 'RcSet', 'FloatOp', code_rc1, inst_flags,
                 CheckRcDecode, IntRcConstructor)

    # Finally, add to the other outputs
    header_output += header_output_rc1
    decoder_output += decoder_output_rc1
    exec_output += exec_output_rc1
}};

// Floating point elementary arithmetic operations. Besides having two
// versions of each instruction for when Rc is set or not, we also have
// to alter lots of special registers depending on the result of the
// operation. The result is always in Ft.sf.
def format FloatArithOp(code, inst_flags = []) {{

    # Code when Rc is set
    code_rc1 = code + readFPSCRCode + computeCR1Code

    # Generate the first class
    (header_output, decoder_output, decode_block, exec_output) = \
        GenAluOp(name, Name, 'FloatOp', code, inst_flags,
                 CheckRcDecode, BasicConstructor)

    # Generate the second class
    (header_output_rc1, decoder_output_rc1, _, exec_output_rc1) = \
        GenAluOp(name, Name + 'RcSet', 'FloatOp', code_rc1, inst_flags,
                 CheckRcDecode, IntRcConstructor)

    # Finally, add to the other outputs
    header_output += header_output_rc1
    decoder_output += decoder_output_rc1
    exec_output += exec_output_rc1
}};

// Floating point rounding and conversion operations. Besides having two
// versions of each instruction for when Rc is set or not, we also have
// to alter lots of special registers depending on the result of the
// operation. The result is always in Ft.sf.
def format FloatConvertOp(code, inst_flags = []) {{

    # Code when Rc is set
    code_rc1 = code + readFPSCRCode + computeCR1Code

    # Generate the first class
    (header_output, decoder_output, decode_block, exec_output) = \
        GenAluOp(name, Name, 'FloatOp', code, inst_flags,
                 CheckRcDecode, BasicConstructor)

    # Generate the second class
    (header_output_rc1, decoder_output_rc1, _, exec_output_rc1) = \
        GenAluOp(name, Name + 'RcSet', 'FloatOp', code_rc1, inst_flags,
                 CheckRcDecode, IntRcConstructor)

    # Finally, add to the other outputs
    header_output += header_output_rc1
    decoder_output += decoder_output_rc1
    exec_output += exec_output_rc1
}};