gem5/src/arch/arm/isa/util.isa
2009-05-12 22:33:05 -07:00

282 lines
8.6 KiB
C++

// -*- mode:c++ -*-
// 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: Stephen Hines
////////////////////////////////////////////////////////////////////
//
// Utility functions for execute methods
//
//
output header {{
// Shift types for ARM instructions
enum ArmShiftType {
LSL = 0,
LSR,
ASR,
ROR
};
enum ArmShiftMode {
};
inline uint32_t number_of_ones(int32_t val)
{
uint32_t ones = 0;
for (int i = 0; i < 32; i++ )
{
if ( val & (1<<i) )
ones++;
}
return ones;
}
}};
output exec {{
static int32_t arm_NEG(int32_t val) { return (val >> 31); }
static int32_t arm_POS(int32_t val) { return ((~val) >> 31); }
// Shift Rm by an immediate value
inline int32_t
shift_rm_imm(uint32_t base, uint32_t shamt, uint32_t type, uint32_t cfval)
{
enum ArmShiftType shiftType;
shiftType = (enum ArmShiftType) type;
switch (shiftType)
{
case LSL:
return (base << shamt);
case LSR:
if (shamt == 0)
return (0);
else
return (base >> shamt);
case ASR:
if (shamt == 0)
return ((uint32_t) ((int32_t) base >> 31L));
else
return ((uint32_t) (((int32_t) base) >> shamt));
case ROR:
//shamt = shamt & 0x1f;
if (shamt == 0)
return (cfval << 31) | (base >> 1); // RRX
else
return (base << (32 - shamt)) | (base >> shamt);
default:
fprintf(stderr, "Unhandled shift type\n");
exit(1);
break;
}
return 0;
}
// Shift Rm by Rs
inline int32_t
shift_rm_rs(uint32_t base, uint32_t shamt, uint32_t type, uint32_t cfval)
{
enum ArmShiftType shiftType;
shiftType = (enum ArmShiftType) type;
switch (shiftType)
{
case LSL:
if (shamt == 0)
return (base);
else if (shamt >= 32)
return (0);
else
return (base << shamt);
case LSR:
if (shamt == 0)
return (base);
else if (shamt >= 32)
return (0);
else
return (base >> shamt);
case ASR:
if (shamt == 0)
return base;
else if (shamt >= 32)
return ((uint32_t) ((int32_t) base >> 31L));
else
return ((uint32_t) (((int32_t) base) >> (int) shamt));
case ROR:
shamt = shamt & 0x1f;
if (shamt == 0)
return (base);
else
return ((base << (32 - shamt)) | (base >> shamt));
default:
fprintf(stderr, "Unhandled shift type\n");
exit(1);
break;
}
return 0;
}
// Generate C for a shift by immediate
inline int32_t
shift_carry_imm(uint32_t base, uint32_t shamt, uint32_t type,
uint32_t cfval)
{
enum ArmShiftType shiftType;
shiftType = (enum ArmShiftType) type;
switch (shiftType)
{
case LSL:
return (base >> (32 - shamt)) & 1;
case LSR:
if (shamt == 0)
return (base >> 31) & 1;
else
return (base >> (shamt - 1)) & 1;
case ASR:
if (shamt == 0)
return (base >> 31L);
else
return ((uint32_t) (((int32_t) base) >> (shamt - 1))) & 1;
case ROR:
shamt = shamt & 0x1f;
if (shamt == 0)
return (base & 1); // RRX
else
return (base >> (shamt - 1)) & 1;
default:
fprintf(stderr, "Unhandled shift type\n");
exit(1);
break;
}
return 0;
}
// Generate C for a shift by Rs
inline int32_t
shift_carry_rs(uint32_t base, uint32_t shamt, uint32_t type, uint32_t cfval)
{
enum ArmShiftType shiftType;
shiftType = (enum ArmShiftType) type;
switch (shiftType)
{
case LSL:
if (shamt == 0)
return (!!cfval);
else if (shamt == 32)
return (base & 1);
else if (shamt > 32)
return (0);
else
return ((base >> (32 - shamt)) & 1);
case LSR:
if (shamt == 0)
return (!!cfval);
else if (shamt == 32)
return (base >> 31);
else if (shamt > 32)
return (0);
else
return ((base >> (shamt - 1)) & 1);
case ASR:
if (shamt == 0)
return (!!cfval);
else if (shamt >= 32)
return (base >> 31L);
else
return (((uint32_t) (((int32_t) base) >> (shamt - 1))) & 1);
case ROR:
if (shamt == 0)
return (!!cfval);
shamt = shamt & 0x1f;
if (shamt == 0)
return (base >> 31); // RRX
else
return ((base >> (shamt - 1)) & 1);
default:
fprintf(stderr, "Unhandled shift type\n");
exit(1);
break;
}
return 0;
}
// Generate the appropriate carry bit for an addition operation
inline int32_t
arm_add_carry(int32_t result, int32_t lhs, int32_t rhs)
{
if ((lhs | rhs) >> 30)
return ((arm_NEG(lhs) && arm_NEG(rhs)) ||
(arm_NEG(lhs) && arm_POS(result)) ||
(arm_NEG(rhs) && arm_POS(result)));
return 0;
}
// Generate the appropriate carry bit for a subtraction operation
inline int32_t
arm_sub_carry(int32_t result, int32_t lhs, int32_t rhs)
{
if ((lhs >= rhs) || ((rhs | lhs) >> 31))
return ((arm_NEG(lhs) && arm_POS(rhs)) ||
(arm_NEG(lhs) && arm_POS(result)) ||
(arm_POS(rhs) && arm_POS(result)));
return 0;
}
inline int32_t
arm_add_overflow(int32_t result, int32_t lhs, int32_t rhs)
{
if ((lhs | rhs) >> 30)
return ((arm_NEG(lhs) && arm_NEG(rhs) && arm_POS(result)) ||
(arm_POS(lhs) && arm_POS(rhs) && arm_NEG(result)));
return 0;
}
inline int32_t
arm_sub_overflow(int32_t result, int32_t lhs, int32_t rhs)
{
if ((lhs >= rhs) || ((rhs | lhs) >> 31))
return ((arm_NEG(lhs) && arm_POS(rhs) && arm_POS(result)) ||
(arm_POS(lhs) && arm_NEG(rhs) && arm_NEG(result)));
return 0;
}
}};