348 lines
7.6 KiB
C
348 lines
7.6 KiB
C
/* This file is part of the program psim.
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Copyright (C) 1994-1996, Andrew Cagney <cagney@highland.com.au>
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Copyright (C) 1997, Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifndef _SIM_ALU_H_
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#define _SIM_ALU_H_
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#include "sim-xcat.h"
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/* 32bit target expressions:
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Each calculation is performed three times using each of the
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signed64, unsigned64 and long integer types. The macro ALU_END
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(in _ALU_RESULT_VAL) then selects which of the three alternative
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results will be used in the final assignment of the target
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register. As this selection is determined at compile time by
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fields in the instruction (OE, EA, Rc) the compiler has sufficient
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information to firstly simplify the selection code into a single
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case and then back anotate the equations and hence eliminate any
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resulting dead code. That dead code being the calculations that,
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as it turned out were not in the end needed.
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64bit arrithemetic is used firstly because it allows the use of
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gcc's efficient long long operators (typically efficiently output
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inline) and secondly because the resultant answer will contain in
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the low 32bits the answer while in the high 32bits is either carry
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or status information. */
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/* 16bit target expressions:
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These are a simplified version of the 32bit target expressions */
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/* 64bit target expressions:
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Unfortunatly 128bit arrithemetic isn't that common. Consequently
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the 32/64 bit trick can not be used. Instead all calculations are
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required to retain carry/overflow information in separate
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variables. Even with this restriction it is still possible for the
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trick of letting the compiler discard the calculation of unneeded
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values */
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/* Macro's to type cast 32bit constants to 64bits */
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#define SIGNED64(val) ((signed64)(signed32)(val))
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#define UNSIGNED64(val) ((unsigned64)(unsigned32)(val))
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/* Start a section of ALU code */
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#define ALU16_BEGIN(VAL) \
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{ \
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signed_word alu_carry_val; \
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unsigned_word alu_overflow_val; \
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ALU16_SET(VAL)
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#define ALU32_BEGIN(VAL) \
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{ \
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natural_word alu_val; \
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unsigned64 alu_carry_val; \
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signed64 alu_overflow_val; \
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ALU32_SET(VAL)
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#define ALU_BEGIN(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_BEGIN)(VAL)
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/* More basic alu operations */
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#define ALU16_SET(VAL) \
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do { \
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alu_carry_val = (unsigned16)(VAL); \
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alu_overflow_val = (signed16)(VAL); \
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} while (0)
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#define ALU32_SET(VAL) \
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do { \
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alu_val = (unsigned32)(VAL); \
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alu_carry_val = (unsigned32)(alu_val); \
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alu_overflow_val = (signed32)(alu_val); \
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} while (0)
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#define ALU64_SET(VAL) \
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do { \
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alu_val = (VAL); \
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alu_carry_val = ((unsigned64)alu_val) >> 32; \
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alu_overflow_val = ((signed64)alu_val) >> 32; \
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} while (0)
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#define ALU_SET(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_SET)(VAL)
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#define ALU16_ADD(VAL) \
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do { \
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alu_carry_val += (unsigned16)(VAL); \
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alu_overflow_val += (signed16)(VAL); \
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} while (0)
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#define ALU32_ADD(VAL) \
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do { \
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alu_val += (VAL); \
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alu_carry_val += (unsigned32)(VAL); \
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alu_overflow_val += (signed32)(VAL); \
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} while (0)
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#define ALU64_ADD(VAL) \
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do { \
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unsigned64 alu_lo = (UNSIGNED64(alu_val) \
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+ UNSIGNED64(VAL)); \
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signed alu_carry = ((alu_lo & BIT(31)) != 0); \
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alu_carry_val = (alu_carry_val \
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+ UNSIGNED64(EXTRACTED(val, 0, 31)) \
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+ alu_carry); \
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alu_overflow_val = (alu_overflow_val \
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+ SIGNED64(EXTRACTED(val, 0, 31)) \
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+ alu_carry); \
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alu_val = alu_val + val; \
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} while (0)
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#define ALU_ADD(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_ADD)(VAL)
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#define ALU16_ADD_CA \
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do { \
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signed carry = ALU_CARRY; \
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ALU16_ADD(carry); \
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} while (0)
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#define ALU32_ADD_CA \
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do { \
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signed carry = ALU_CARRY; \
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ALU32_ADD(carry); \
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} while (0)
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#define ALU64_ADD_CA \
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do { \
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signed carry = ALU_CARRY; \
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ALU64_ADD(carry); \
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} while (0)
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#define ALU_ADD_CA XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_ADD_CA)
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#define ALU16_SUB(VAL) \
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do { \
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alu_carry_val -= (unsigned16)(VAL); \
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alu_overflow_val -= (signed16)(VAL); \
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} while (0)
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#define ALU32_SUB(VAL) \
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do { \
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alu_val -= (VAL); \
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alu_carry_val -= (unsigned32)(VAL); \
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alu_overflow_val -= (signed32)(VAL); \
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} while (0)
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#define ALU64_SUB(VAL) \
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do { \
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error("ALU_SUB64"); \
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} while (0)
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#define ALU_SUB(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_SUB)(VAL)
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#define ALU16_SUB_CA \
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do { \
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signed carry = ALU_CARRY; \
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ALU16_SUB(carry); \
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} while (0)
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#define ALU32_SUB_CA \
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do { \
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signed carry = ALU_CARRY; \
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ALU32_SUB(carry); \
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} while (0)
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#define ALU64_SUB_CA \
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do { \
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signed carry = ALU_CARRY; \
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ALU64_SUB(carry); \
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} while (0)
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#define ALU_SUB_CA XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_SUB_CA)
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#define ALU16_OR(VAL) \
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do { \
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error("ALU16_OR"); \
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} while (0)
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#define ALU32_OR(VAL) \
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do { \
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alu_val |= (VAL); \
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alu_carry_val = (unsigned32)(alu_val); \
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alu_overflow_val = (signed32)(alu_val); \
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} while (0)
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#define ALU64_OR(VAL) \
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do { \
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error("ALU_OR64"); \
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} while (0)
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#define ALU_OR(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_OR)(VAL)
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#define ALU16_XOR(VAL) \
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do { \
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error("ALU16_XOR"); \
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} while (0)
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#define ALU32_XOR(VAL) \
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do { \
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alu_val ^= (VAL); \
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alu_carry_val = (unsigned32)(alu_val); \
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alu_overflow_val = (signed32)(alu_val); \
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} while (0)
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#define ALU64_XOR(VAL) \
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do { \
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error("ALU_XOR64"); \
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} while (0)
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#define ALU_XOR(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_XOR)(VAL)
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#define ALU16_NEGATE \
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do { \
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error("ALU_NEGATE16"); \
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} while (0)
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#define ALU32_NEGATE \
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do { \
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alu_val = -alu_val; \
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alu_carry_val = -alu_carry_val; \
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alu_overflow_val = -alu_overflow_val; \
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} while(0)
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#define ALU64_NEGATE \
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do { \
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error("ALU_NEGATE64"); \
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} while (0)
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#define ALU_NEGATE XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_NEGATE)
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#define ALU16_AND(VAL) \
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do { \
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error("ALU_AND16"); \
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} while (0)
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#define ALU32_AND(VAL) \
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do { \
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alu_val &= (VAL); \
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alu_carry_val = (unsigned32)(alu_val); \
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alu_overflow_val = (signed32)(alu_val); \
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} while (0)
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#define ALU64_AND(VAL) \
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do { \
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error("ALU_AND64"); \
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} while (0)
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#define ALU_AND(VAL) XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_AND)(VAL)
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#define ALU16_NOT(VAL) \
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do { \
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error("ALU_NOT16"); \
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} while (0)
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#define ALU32_NOT \
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do { \
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signed64 new_alu_val = ~alu_val; \
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ALU_SET(new_alu_val); \
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} while (0)
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#define ALU64_NOT \
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do { \
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error("ALU_NOT64"); \
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} while (0)
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#define ALU_NOT XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_NOT)
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/* Make available various results */
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/* overflow occures if the sign bit differs from the carry bit */
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#define ALU16_HAD_OVERFLOW \
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(!(alu_overflow_val & MSBIT32 (0)) != !(alu_overflow_val & MSBIT32 (16)))
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#define ALU32_HAD_OVERFLOW \
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((((unsigned64)(alu_overflow_val & BIT64(0))) >> 32) \
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!= (alu_overflow_val & MSBIT64(32)))
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#define ALU_HAD_OVERFLOW XCONCAT3(ALU,WITH_TARGET_WORD_BITSIZE,_HAD_OVERFLOW)
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/* carry found in bit before sign */
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#define ALU16_HAD_CARRY \
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(alu_carry_val & MSBIT32(16))
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#define ALU32_HAD_CARRY \
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(alu_carry_val & MSBIT64(31))
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#endif
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