binutils-gdb/sim/msp430/msp430-sim.h
Jozef Lawrynowicz e8a387fb5f MSP430: sim: Fix incorrect simulation of unsigned widening multiply
Operand sizes used for simulation of MSP430 hardware multiply
operations are not aligned with the sizes used on the target, resulting
in the simulator storing signed operands with too much precision.

Additionally, simulation of unsigned multiplication is missing explicit
casts to prevent any implicit sign extension.

gcc.c-torture/execute/pr91450-1.c uses unsigned widening multiplication
of 32-bit operands -4 and 2, to produce a 64-bit result:
0xffff fffc * 0x2 = 0x1 ffff fff8

If -4 is stored in 64-bit precision, then the multiplication is
essentially signed and the result is -8 in 64-bit precision
(0xffff ffff ffff fffc), which is not correct.

sim/msp430/ChangeLog:

	* msp430-sim.c (put_op): For unsigned multiplication, explicitly cast
	operands to the unsigned type before multiplying.
	* msp430-sim.h (struct msp430_cpu_state): Fix types used to store hwmult
	operands.

sim/testsuite/sim/msp430/ChangeLog:

	* mpyull_hwmult.s: New test.
2020-08-05 15:02:30 +01:00

50 lines
1.5 KiB
C

/* Simulator for TI MSP430 and MSP430x processors.
Copyright (C) 2012-2020 Free Software Foundation, Inc.
Contributed by Red Hat, Inc.
This file is part of simulators.
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 3 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, see <http://www.gnu.org/licenses/>. */
#ifndef _MSP430_SIM_H_
#define _MSP430_SIM_H_
typedef enum { UNSIGN_32, SIGN_32, UNSIGN_MAC_32, SIGN_MAC_32 } hwmult_type;
typedef enum { UNSIGN_64, SIGN_64 } hw32mult_type;
struct msp430_cpu_state
{
int regs[16];
int cio_breakpoint;
int cio_buffer;
hwmult_type hwmult_type;
unsigned16 hwmult_op1;
unsigned16 hwmult_op2;
unsigned32 hwmult_result;
signed32 hwmult_signed_result;
unsigned32 hwmult_accumulator;
signed32 hwmult_signed_accumulator;
hw32mult_type hw32mult_type;
unsigned32 hw32mult_op1;
unsigned32 hw32mult_op2;
unsigned64 hw32mult_result;
};
#define HWMULT(SD, FIELD) MSP430_CPU (SD)->state.FIELD
#endif