fpmodule.inl

来自「优龙2410linux2.6.8内核源代码」· INL 代码 · 共 75 行

/*
    NetWinder Floating Point Emulator
    (c) Rebel.COM, 1998,1999

    Direct questions, comments to Scott Bambrough <[e-mail]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

static inline unsigned long readRegister(const unsigned int nReg)
{
	/* Note: The CPU thinks it has dealt with the current instruction.
	   As a result the program counter has been advanced to the next
	   instruction, and points 4 bytes beyond the actual instruction
	   that caused the invalid instruction trap to occur.  We adjust
	   for this in this routine.  LDF/STF instructions with Rn = PC
	   depend on the PC being correct, as they use PC+8 in their
	   address calculations. */
	unsigned long *userRegisters = GET_USERREG();
	unsigned int val = userRegisters[nReg];
	if (REG_PC == nReg)
		val -= 4;
	return val;
}

static inline void
writeRegister(const unsigned int nReg, const unsigned long val)
{
	unsigned long *userRegisters = GET_USERREG();
	userRegisters[nReg] = val;
}

static inline unsigned long readCPSR(void)
{
	return (readRegister(REG_CPSR));
}

static inline void writeCPSR(const unsigned long val)
{
	writeRegister(REG_CPSR, val);
}

static inline unsigned long readConditionCodes(void)
{
#ifdef __FPEM_TEST__
	return (0);
#else
	return (readCPSR() & CC_MASK);
#endif
}

static inline void writeConditionCodes(const unsigned long val)
{
	unsigned long *userRegisters = GET_USERREG();
	unsigned long rval;
	/*
	 * Operate directly on userRegisters since
	 * the CPSR may be the PC register itself.
	 */
	rval = userRegisters[REG_CPSR] & ~CC_MASK;
	userRegisters[REG_CPSR] = rval | (val & CC_MASK);
}