Re: [PATCH] sim: pru: Add support for LMBD instruction

[Andrew Burgess <andrew.burgess@embecosm.com>]

* Dimitar Dimitrov <dimitar@dinux.eu> [2020-11-10 21:11:06 +0200]:

> Binutils support for LMBD instruction was merged [1]. So add it also
> to simulator.
> 
> LMBD instruction does left-most-bit-detection. It returns 32 if
> the given bit value is not found in the provided word value.
> 
> [1] https://sourceware.org/pipermail/binutils/2020-October/113901.html
> 
> sim/pru/ChangeLog:
> 
> 	* pru.h (RS1SEL): New macro.
> 	(RS1_WIDTH): New macro.
> 	* pru.isa: Describe the LMBD instruction.
> 
> sim/testsuite/sim/pru/ChangeLog:
> 
> 	* lmbd.s: New test.

LGTM.  Thanks for doing this.

Andrew


> 
> Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>
> ---
>  sim/pru/pru.h                |  2 ++
>  sim/pru/pru.isa              | 15 +++++++++
>  sim/testsuite/sim/pru/lmbd.s | 61 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 78 insertions(+)
>  create mode 100644 sim/testsuite/sim/pru/lmbd.s
> 
> diff --git a/sim/pru/pru.h b/sim/pru/pru.h
> index 240fc30010..cbcc3ef9d7 100644
> --- a/sim/pru/pru.h
> +++ b/sim/pru/pru.h
> @@ -58,6 +58,8 @@
>  
>  #define XBBO_BASEREG (CPU.regs[GET_INSN_FIELD (RS1, inst)])
>  
> +#define RS1SEL GET_INSN_FIELD (RS1SEL, inst)
> +#define RS1_WIDTH regsel_width (RS1SEL)
>  #define RDSEL GET_INSN_FIELD (RDSEL, inst)
>  #define RD_WIDTH regsel_width (RDSEL)
>  #define RD_REGN GET_INSN_FIELD (RD, inst)
> diff --git a/sim/pru/pru.isa b/sim/pru/pru.isa
> index 050154560b..c7860d0191 100644
> --- a/sim/pru/pru.isa
> +++ b/sim/pru/pru.isa
> @@ -247,3 +247,18 @@ INSTRUCTION (iloop,
>  		LOOP_IN_PROGRESS = 1;
>  		PC++;
>  	     })
> +
> +INSTRUCTION (lmbd,
> +	     {
> +	     int lmbd_i;
> +
> +	     OP2 = (IO ? IMM8 : RS2);
> +
> +	     for (lmbd_i = RS1_WIDTH - 1; lmbd_i >= 0; lmbd_i--)
> +	       {
> +		 if (!(((RS1 >> lmbd_i) ^ OP2) & 1))
> +		   break;
> +	       }
> +	     RD = (lmbd_i < 0) ? 32 : lmbd_i;
> +	     PC++;
> +	     })
> diff --git a/sim/testsuite/sim/pru/lmbd.s b/sim/testsuite/sim/pru/lmbd.s
> new file mode 100644
> index 0000000000..9a9e7827b2
> --- /dev/null
> +++ b/sim/testsuite/sim/pru/lmbd.s
> @@ -0,0 +1,61 @@
> +# Check that lmbd insn works.
> +# mach: pru
> +
> +# Copyright (C) 2020 Free Software Foundation, Inc.
> +# Contributed by Dimitar Dimitrov <dimitar@dinux.eu>
> +#
> +# This file is part of the GNU 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/>.
> +
> +.include "testutils.inc"
> +
> +	start
> +
> +	ldi32 r14, 0xffffffff
> +	ldi32 r15, 0x0
> +	ldi32 r16, 0x40000000
> +	ldi32 r17, 8
> +
> +	lmbd r0, r14, 0
> +	qbne 2f, r0, 32
> +
> +	lmbd r0, r14, 1
> +	qbne 2f, r0, 31
> +
> +	lmbd r0, r15, 1
> +	qbne 2f, r0, 32
> +
> +	lmbd r0, r15, 0
> +	qbne 2f, r0, 31
> +
> +	lmbd r0, r16, r15
> +	qbne 2f, r0, 31
> +
> +	lmbd r0, r16, 1
> +	qbne 2f, r0, 30
> +
> +	lmbd r0, r14.w1, 1
> +	qbne 2f, r0, 15
> +
> +	lmbd r0, r17.b0, 1
> +	qbne 2f, r0, 3
> +
> +	lmbd r0, r17.b0, r15
> +	qbne 2f, r0, 7
> +
> +
> +1:
> +	pass
> +2:	fail
> -- 
> 2.20.1
>