From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20464 invoked by alias); 22 Jun 2004 21:30:51 -0000 Mailing-List: contact binutils-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sources.redhat.com Received: (qmail 20447 invoked from network); 22 Jun 2004 21:30:49 -0000 Received: from unknown (HELO jurand.ds.pg.gda.pl) (153.19.208.2) by sourceware.org with SMTP; 22 Jun 2004 21:30:49 -0000 Received: by jurand.ds.pg.gda.pl (Postfix, from userid 1011) id 7C4E647831; Tue, 22 Jun 2004 23:30:48 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by jurand.ds.pg.gda.pl (Postfix) with ESMTP id 631AB4762E; Tue, 22 Jun 2004 23:30:48 +0200 (CEST) Date: Tue, 22 Jun 2004 21:30:00 -0000 From: "Maciej W. Rozycki" To: cgd@broadcom.com Cc: David Daney , Ralf Baechle , linux-mips@linux-mips.org, binutils@sources.redhat.com Subject: Re: [Patch] / 0 should send SIGFPE not SIGTRAP... In-Reply-To: Message-ID: References: <40C9F5A4.2050606@avtrex.com> <40C9F5FE.8030607@avtrex.com> <40C9F7F0.50501@avtrex.com> Organization: Technical University of Gdansk MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SW-Source: 2004-06/txt/msg00406.txt.bz2 On Fri, 11 Jun 2004 cgd@broadcom.com wrote: > in retrospect, the 'B' variation probably wasn't the greatest idea. > > If it were removed (leaving 'c' and 'c','q' variations), I don't know > that any real harm would occur. > > It may be very confusing to people who expect that the break code will > translate into the instruction in an obvious way, and obviously it > would mess up use of 20-bit codes, but i don't know how prevalent that > is. > > Unfortunately, at this point, Linux should probably accept the > divide-by-zero code in both locations. > > > (Really, from day one, assemblers probably should have accepted a > 20-bit code. I just checked my copy of the Kane r2000/r3000 book, and > it was 20-bit all the way back then. If i had to guess, i'd guess > that gas was copying a non-gnu assembler's behaviour. In any case, > water under the bridge.) As it's at least annoying to have different break codes for divisions expanded by gcc explicitly and ones created implicitly by gas, here's the most reasonable (IMO) approach to fix that. I think it should have been implemented this way originally (if at all). gas/testsuite/: 2004-06-22 Maciej W. Rozycki * gas/mips/break20.s: Test the "break20" alias. * gas/mips/break20.d: Results for the test. * gas/mips/mips32.s: Replace "break" with "break20". * gas/mips/set-arch.s: Likewise. * gas/mips/mips32.d: Adjust for the new output. * gas/mips/set-arch.d: Likewise. opcodes/: 2004-06-22 Maciej W. Rozycki * mips-opc.c (mips_builtin_opcodes): Replace the MIPS32 ISA specific "break" encoding with a "break20" alias accepted for any ISA. I decided to give a precedence to "break x,y" over "break20 z" to avoid perhaps a bit surprising output in `objdump'. The question is: does anyone know of possible troubles with this change? Chances are someone depends on the current semantics for -march=mips32/mips64, but that's fragile anyway as building with a different setting results in different code. Or should we get rid of the 20-bit "break" completely? The two-argument version provides the same functionality, although the 10-bit codes to be used do not map to the 20-bit equivalent "optically" very well. Especially if decimal notation is used. Note the same problem appears to be the case with "sdbbp". It could be handled similarly, but given the limited use of "sdbbp" for non-MIPS32/MIPS64 ISAs it may not be worth the hassle. I see no problem writing a similar fix if desired, though. Maciej -- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available + binutils-2.15.91-20040615-mips-break20.patch diff -up --recursive --new-file binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/break20.d binutils-2.15.91-20040615/gas/testsuite/gas/mips/break20.d --- binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/break20.d 2003-05-08 03:25:31.000000000 +0000 +++ binutils-2.15.91-20040615/gas/testsuite/gas/mips/break20.d 2004-06-17 21:03:30.000000000 +0000 @@ -10,9 +10,13 @@ Disassembly of section .text: 0+0008 <[^>]*> break 0x14 0+000c <[^>]*> break 0x14,0x28 0+0010 <[^>]*> break 0x3ff,0x3ff -0+0014 <[^>]*> sdbbp -0+0018 <[^>]*> sdbbp -0+001c <[^>]*> sdbbp 0x14 -0+0020 <[^>]*> sdbbp 0x14,0x28 -0+0024 <[^>]*> sdbbp 0x3ff,0x3ff +0+0014 <[^>]*> break +0+0018 <[^>]*> break 0x0,0x14 +0+001c <[^>]*> break 0x14,0x28 +0+0020 <[^>]*> break 0x3ff,0x3ff +0+0024 <[^>]*> sdbbp +0+0028 <[^>]*> sdbbp +0+002c <[^>]*> sdbbp 0x14 +0+0030 <[^>]*> sdbbp 0x14,0x28 +0+0034 <[^>]*> sdbbp 0x3ff,0x3ff ... diff -up --recursive --new-file binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/break20.s binutils-2.15.91-20040615/gas/testsuite/gas/mips/break20.s --- binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/break20.s 1999-08-10 14:24:45.000000000 +0000 +++ binutils-2.15.91-20040615/gas/testsuite/gas/mips/break20.s 2004-06-17 19:57:51.000000000 +0000 @@ -6,6 +6,11 @@ foo: break 20,40 break 1023,1023 + break20 0 + break20 20 + break20 20520 + break20 1048575 + sdbbp sdbbp 0 sdbbp 20 diff -up --recursive --new-file binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/mips32.d binutils-2.15.91-20040615/gas/testsuite/gas/mips/mips32.d --- binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/mips32.d 2003-05-08 03:25:35.000000000 +0000 +++ binutils-2.15.91-20040615/gas/testsuite/gas/mips/mips32.d 2004-06-17 21:15:04.000000000 +0000 @@ -48,7 +48,7 @@ Disassembly of section .text: 0+0098 <[^>]*> 4359e260 wait 0x56789 0+009c <[^>]*> 0000000d break 0+00a0 <[^>]*> 0000000d break -0+00a4 <[^>]*> 0048d14d break 0x12345 +0+00a4 <[^>]*> 0048d14d break 0x48,0x345 0+00a8 <[^>]*> 7000003f sdbbp 0+00ac <[^>]*> 7000003f sdbbp 0+00b0 <[^>]*> 7159e27f sdbbp 0x56789 diff -up --recursive --new-file binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/mips32.s binutils-2.15.91-20040615/gas/testsuite/gas/mips/mips32.s --- binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/mips32.s 2002-09-05 03:25:40.000000000 +0000 +++ binutils-2.15.91-20040615/gas/testsuite/gas/mips/mips32.s 2004-06-17 21:13:22.000000000 +0000 @@ -62,7 +62,7 @@ text_label: # different. break break 0 # disassembles without code - break 0x12345 + break20 0x12345 sdbbp sdbbp 0 # disassembles without code sdbbp 0x56789 diff -up --recursive --new-file binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/set-arch.d binutils-2.15.91-20040615/gas/testsuite/gas/mips/set-arch.d --- binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/set-arch.d 2003-10-01 03:25:36.000000000 +0000 +++ binutils-2.15.91-20040615/gas/testsuite/gas/mips/set-arch.d 2004-06-17 21:17:46.000000000 +0000 @@ -160,7 +160,7 @@ Disassembly of section \.text: 00000260 <[^>]*> 4359e260 wait 0x56789 00000264 <[^>]*> 0000000d break 00000268 <[^>]*> 0000000d break -0000026c <[^>]*> 0048d14d break 0x12345 +0000026c <[^>]*> 0048d14d break 0x48,0x345 00000270 <[^>]*> 7000003f sdbbp 00000274 <[^>]*> 7000003f sdbbp 00000278 <[^>]*> 7159e27f sdbbp 0x56789 diff -up --recursive --new-file binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/set-arch.s binutils-2.15.91-20040615/gas/testsuite/gas/mips/set-arch.s --- binutils-2.15.91-20040615.macro/gas/testsuite/gas/mips/set-arch.s 2003-06-29 19:41:33.000000000 +0000 +++ binutils-2.15.91-20040615/gas/testsuite/gas/mips/set-arch.s 2004-06-17 21:18:01.000000000 +0000 @@ -204,7 +204,7 @@ text_label: # different. break break 0 # disassembles without code - break 0x12345 + break20 0x12345 sdbbp sdbbp 0 # disassembles without code sdbbp 0x56789 diff -up --recursive --new-file binutils-2.15.91-20040615.macro/opcodes/mips-opc.c binutils-2.15.91-20040615/opcodes/mips-opc.c --- binutils-2.15.91-20040615.macro/opcodes/mips-opc.c 2003-11-19 04:25:23.000000000 +0000 +++ binutils-2.15.91-20040615/opcodes/mips-opc.c 2004-06-17 19:46:23.000000000 +0000 @@ -274,9 +274,9 @@ const struct mips_opcode mips_builtin_op {"bnel", "s,t,p", 0x54000000, 0xfc000000, CBL|RD_s|RD_t, I2|T3 }, {"bnel", "s,I,p", 0, (int) M_BNEL_I, INSN_MACRO, I2|T3 }, {"break", "", 0x0000000d, 0xffffffff, TRAP, I1 }, -{"break", "B", 0x0000000d, 0xfc00003f, TRAP, I32 }, {"break", "c", 0x0000000d, 0xfc00ffff, TRAP, I1 }, {"break", "c,q", 0x0000000d, 0xfc00003f, TRAP, I1 }, +{"break20", "B", 0x0000000d, 0xfc00003f, TRAP, I1 }, {"c.f.d", "S,T", 0x46200030, 0xffe007ff, RD_S|RD_T|WR_CC|FP_D, I1 }, {"c.f.d", "M,S,T", 0x46200030, 0xffe000ff, RD_S|RD_T|WR_CC|FP_D, I4|I32 }, {"c.f.s", "S,T", 0x46000030, 0xffe007ff, RD_S|RD_T|WR_CC|FP_S, I1 },