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Re: RFA: XStormy16: Fix implementation of MOVF instruction

From: Dave Brolley <brolley at redhat dot com>
To: Nick Clifton <nickc at redhat dot com>
Cc: cgen at sourceware dot org, sid at sourceware dot org, dj at redhat dot com
Date: Mon, 01 Nov 2010 11:48:22 -0400
Subject: Re: RFA: XStormy16: Fix implementation of MOVF instruction
References: <m3vd4mpri0.fsf@redhat.com>

Hi Nick,

I don't know that this port has a maintainer for CGEN/SID. However, I think that testing against a specific test case which exhibits the bug and running the SID testsuite for --target=xstormy16-elf should be sufficient. I see that there is no test case for this insn in sid/component/testsuite/sidcomp.cgen-cpu.xstormy16, so please add one before running the test suite.

Dave

On 10/28/2010 05:59 AM, Nick Clifton wrote:

Hi Guys,

   The patch below fixes the emulation of the XStormy16's MOVF
   instruction.  There were two problems - firstly when memory addresses
   were being aligned they were also being truncated to 16-bits.  (The
   MOVF instruction allows access to a 32-bit address space).  Secondly
   the pre-decrement and post-increment addressing modes were not
   propagating the carry into the base register.

Tested by running lots of different xstormy16 programs under SID.

OK to apply ?

Cheers
   Nick Clifton

cgen/ChangeLog
2010-10-28  Nick Clifton<nickc@redhat.com>

	* cpu/xstormy16.cpu (alignfix-mem-far): New macro.  Like
         alignfix-mem, but works with 32-bit addresses.
         (set-alignfix-mem-far): New macro.  Like set-alignfix-mem but
         works with 32-bit addresses.
         (movfgrgri, movfgrgripostinc, movfgrgripredec, movfgrgrii,
         movfgrgriipostinc, movfgrgriipredec): Use alignfix-mem-far.
         (movfgrigr, movfgripostincgr, movfgripredecgr): Use
         set-alignfix-mem-far.
	(movfgrgriipostinc, movfgriipostincgr): Propagate addition to
         source register into base register.
	(movfgrgriipredec, movfgriipredecgr): Propagate subtraction from
         source register into base register.

sid/component/cgen-cpu/xstormy16/ChangeLog
2010-10-28  Nick Clifton<nickc@redhat.com>

* xstormy16-sem.cxx: Regenerate.

Index: cgen/cpu/xstormy16.cpu
===================================================================
RCS file: /cvs/src/src/cgen/cpu/xstormy16.cpu,v
retrieving revision 1.15
diff -u -3 -p -r1.15 xstormy16.cpu
--- cgen/cpu/xstormy16.cpu	1 Jun 2010 22:06:50 -0000	1.15
+++ cgen/cpu/xstormy16.cpu	28 Oct 2010 09:44:15 -0000
@@ -524,6 +524,12 @@
  (define-pmacro (set-alignfix-mem where what)
    (set (mem HI (and where #xFFFE)) what))

+(define-pmacro (alignfix-mem-far where)
+  (mem HI (and where #xFFFFFFFE)))
+
+(define-pmacro (set-alignfix-mem-far where what)
+  (set (mem HI (and where #xFFFFFFFE)) what))
+
  (dni movlmemimm
       "Move immediate to low memory"
       ()
@@ -824,7 +830,7 @@
       ("movf$ws2 $Rdm,($Rs)")
       (+ OP1_7 OP2A_4 ws2 Rs OP4M_0 Rdm)
       (if ws2
-	 (set-psw Rdm (index-of Rdm) (alignfix-mem (or (sll SI R8 16) Rs)) ws2)
+	 (set-psw Rdm (index-of Rdm) (alignfix-mem-far (or (sll SI R8 16) Rs)) ws2)
  	 (set-psw Rdm (index-of Rdm) (and #xFF (mem QI (or (sll SI R8 16) Rs))) ws2))
       ()
  )
@@ -836,7 +842,7 @@
       (+ OP1_6 OP2A_4 ws2 Rs OP4M_0 Rdm)
       (sequence ()
  	       (if ws2
-		   (set-psw Rdm (index-of Rdm) (alignfix-mem (join SI HI R8 Rs)) ws2)
+		   (set-psw Rdm (index-of Rdm) (alignfix-mem-far (join SI HI R8 Rs)) ws2)
  		   (set-psw Rdm (index-of Rdm) (and #xFF (mem QI (join SI HI R8 Rs))) ws2))
  	       (set Rs (add Rs (add ws2 1))))
       ()
@@ -850,7 +856,7 @@
       (sequence ()
  	       (set Rs (sub Rs (add ws2 1)))
  	       (if ws2
-		   (set-psw Rdm (index-of Rdm) (alignfix-mem (join SI HI R8 Rs)) ws2)
+		   (set-psw Rdm (index-of Rdm) (alignfix-mem-far (join SI HI R8 Rs)) ws2)
  		   (set-psw Rdm (index-of Rdm) (and #xFF (mem QI (join SI HI R8 Rs))) ws2)))
       ()
  )
@@ -862,7 +868,7 @@
       (+ OP1_7 OP2A_6 ws2 Rs OP4M_0 Rdm)
       (sequence ()
  	       (if ws2
-		   (set-alignfix-mem (join SI HI R8 Rs) Rdm)
+		   (set-alignfix-mem-far (join SI HI R8 Rs) Rdm)
  		   (set (mem QI (join SI HI R8 Rs)) Rdm))
  	       (set-psw-nowrite (index-of Rdm) Rdm ws2))
       ()
@@ -875,7 +881,7 @@
       (+ OP1_6 OP2A_6 ws2 Rs OP4M_0 Rdm)
       (sequence ()
  	       (if ws2
-		   (set-alignfix-mem (join SI HI R8 Rs) Rdm)
+		   (set-alignfix-mem-far (join SI HI R8 Rs) Rdm)
  		   (set (mem QI (join SI HI R8 Rs)) Rdm))
  	       (set-psw-nowrite (index-of Rdm) Rdm ws2)
  	       (set Rs (add Rs (add ws2 1))))
@@ -891,7 +897,7 @@
  	       (set-psw-nowrite (index-of Rdm) Rdm ws2)
  	       (set Rs (sub Rs (add ws2 1)))
  	       (if ws2
-		   (set-alignfix-mem (join SI HI R8 Rs) Rdm)
+		   (set-alignfix-mem-far (join SI HI R8 Rs) Rdm)
  		   (set (mem QI (join SI HI R8 Rs)) Rdm)))
       ()
  )
@@ -902,7 +908,7 @@
       ("movf$ws2 $Rdm,($Rb,$Rs,$imm12)")
       (+ OP1_7 OP2A_4 ws2 Rs OP4M_1 Rdm OP5A_0 Rb imm12)
       (if ws2
-	 (set-psw Rdm (index-of Rdm) (alignfix-mem (add (join SI HI Rb Rs) imm12)) ws2)
+	 (set-psw Rdm (index-of Rdm) (alignfix-mem-far (add (join SI HI Rb Rs) imm12)) ws2)
  	 (set-psw Rdm (index-of Rdm) (and #xFF (mem QI (add (join SI HI Rb Rs) imm12))) ws2))
       ()
  )
@@ -914,9 +920,13 @@
       (+ OP1_6 OP2A_4 ws2 Rs OP4M_1 Rdm OP5A_0 Rb imm12)
       (sequence ()
  	       (if ws2
-		   (set-psw Rdm (index-of Rdm) (alignfix-mem (add (join SI HI Rb Rs) imm12)) ws2)
+		   (set-psw Rdm (index-of Rdm) (alignfix-mem-far (add (join SI HI Rb Rs) imm12)) ws2)
  		   (set-psw Rdm (index-of Rdm) (and #xFF (mem QI (add (join SI HI Rb Rs) imm12))) ws2))
-	       (set Rs (add Rs (add ws2 1))))
+	       (set Rs (add Rs (add ws2 1)))
+	       ; Note - despite the XStormy16 ISA documentation the
+	       ; addition *is* propogated into the base register.
+	       (if (eq Rs 0) (set Rb (add Rb 1)))
+	       )
       ()
  )

@@ -926,9 +936,12 @@
       ("movf$ws2 $Rdm,($Rb,--$Rs,$imm12)")
       (+ OP1_6 OP2A_C ws2 Rs OP4M_1 Rdm OP5A_0 Rb imm12)
       (sequence ()
+	       ; Note - despite the XStormy16 ISA documentation the
+	       ; subtraction *is* propogated into the base register.
+	       (if (eq Rs 0) (set Rb (sub Rb 1)))
  	       (set Rs (sub Rs (add ws2 1)))
  	       (if ws2
-		   (set-psw Rdm (index-of Rdm) (alignfix-mem (add (join SI HI Rb Rs) imm12)) ws2)
+		   (set-psw Rdm (index-of Rdm) (alignfix-mem-far (add (join SI HI Rb Rs) imm12)) ws2)
  		   (set-psw Rdm (index-of Rdm) (and #xFF (mem QI (add (join SI HI Rb Rs) imm12))) ws2)))
       ()
  )
@@ -958,7 +971,11 @@
  		   (set (mem HI (and (add (join SI HI Rb Rs) imm12) #xFFFFFFFE)) Rdm)
  		   (set (mem QI (add (join SI HI Rb Rs) imm12)) Rdm))
  	       (set-psw-nowrite (index-of Rdm) Rdm ws2)
-	       (set Rs (add Rs (add ws2 1))))
+	       (set Rs (add Rs (add ws2 1)))
+	       ; Note - despite the XStormy16 ISA documentation the
+	       ; addition *is* propogated into the base register.
+	       (if (eq Rs 0) (set Rb (add Rb 1)))
+	       )
       ()
  )

@@ -968,6 +985,9 @@
       ("movf$ws2 ($Rb,--$Rs,$imm12),$Rdm")
       (+ OP1_6 OP2A_E ws2 Rs OP4M_1 Rdm OP5A_0 Rb imm12)
       (sequence ()
+	       ; Note - despite the XStormy16 ISA documentation the
+	       ; subtraction *is* propogated into the base register.
+	       (if (eq Rs 0) (set Rb (sub Rb 1)))
  	       (set Rs (sub Rs (add ws2 1)))
  	       (set-psw-nowrite (index-of Rdm) Rdm ws2)
  	       (if ws2

Follow-Ups:
- Re: RFA: XStormy16: Fix implementation of MOVF instruction
  - From: Nick Clifton

References:
- RFA: XStormy16: Fix implementation of MOVF instruction
  - From: Nick Clifton

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