(thanks to Gabe's include feature!). arch/alpha/isa/main.isa: Split out into multiple .isa files. --HG-- extra : convert_revision : 30d8edf74ea194d4a208febf1e66edc72a7dbd5d
112 lines
4.2 KiB
C++
112 lines
4.2 KiB
C++
// -*- mode:c++ -*-
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// Copyright (c) 2003-2005 The Regents of The University of Michigan
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met: redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer;
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// redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution;
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// neither the name of the copyright holders nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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output exec {{
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/// Return opa + opb, summing carry into third arg.
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inline uint64_t
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addc(uint64_t opa, uint64_t opb, int &carry)
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{
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uint64_t res = opa + opb;
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if (res < opa || res < opb)
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++carry;
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return res;
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}
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/// Multiply two 64-bit values (opa * opb), returning the 128-bit
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/// product in res_hi and res_lo.
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inline void
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mul128(uint64_t opa, uint64_t opb, uint64_t &res_hi, uint64_t &res_lo)
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{
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// do a 64x64 --> 128 multiply using four 32x32 --> 64 multiplies
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uint64_t opa_hi = opa<63:32>;
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uint64_t opa_lo = opa<31:0>;
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uint64_t opb_hi = opb<63:32>;
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uint64_t opb_lo = opb<31:0>;
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res_lo = opa_lo * opb_lo;
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// The middle partial products logically belong in bit
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// positions 95 to 32. Thus the lower 32 bits of each product
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// sum into the upper 32 bits of the low result, while the
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// upper 32 sum into the low 32 bits of the upper result.
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uint64_t partial1 = opa_hi * opb_lo;
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uint64_t partial2 = opa_lo * opb_hi;
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uint64_t partial1_lo = partial1<31:0> << 32;
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uint64_t partial1_hi = partial1<63:32>;
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uint64_t partial2_lo = partial2<31:0> << 32;
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uint64_t partial2_hi = partial2<63:32>;
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// Add partial1_lo and partial2_lo to res_lo, keeping track
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// of any carries out
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int carry_out = 0;
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res_lo = addc(partial1_lo, res_lo, carry_out);
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res_lo = addc(partial2_lo, res_lo, carry_out);
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// Now calculate the high 64 bits...
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res_hi = (opa_hi * opb_hi) + partial1_hi + partial2_hi + carry_out;
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}
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/// Map 8-bit S-floating exponent to 11-bit T-floating exponent.
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/// See Table 2-2 of Alpha AHB.
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inline int
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map_s(int old_exp)
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{
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int hibit = old_exp<7:>;
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int lobits = old_exp<6:0>;
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if (hibit == 1) {
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return (lobits == 0x7f) ? 0x7ff : (0x400 | lobits);
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}
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else {
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return (lobits == 0) ? 0 : (0x380 | lobits);
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}
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}
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/// Convert a 32-bit S-floating value to the equivalent 64-bit
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/// representation to be stored in an FP reg.
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inline uint64_t
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s_to_t(uint32_t s_val)
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{
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uint64_t tmp = s_val;
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return (tmp<31:> << 63 // sign bit
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| (uint64_t)map_s(tmp<30:23>) << 52 // exponent
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| tmp<22:0> << 29); // fraction
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}
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/// Convert a 64-bit T-floating value to the equivalent 32-bit
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/// S-floating representation to be stored in memory.
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inline int32_t
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t_to_s(uint64_t t_val)
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{
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return (t_val<63:62> << 30 // sign bit & hi exp bit
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| t_val<58:29>); // rest of exp & fraction
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}
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}};
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