From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751329AbbHWGPX (ORCPT ); Sun, 23 Aug 2015 02:15:23 -0400 Received: from mail-wi0-f172.google.com ([209.85.212.172]:36594 "EHLO mail-wi0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750905AbbHWGPV (ORCPT ); Sun, 23 Aug 2015 02:15:21 -0400 Date: Sun, 23 Aug 2015 08:15:17 +0200 From: Ingo Molnar To: Denys Vlasenko Cc: Borislav Petkov , "H. Peter Anvin" , Andy Lutomirski , Kees Cook , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/math-emu: Add support for FCMOVcc and F[U]COMI[P] insns Message-ID: <20150823061517.GA18134@gmail.com> References: <1440152395-19818-1-git-send-email-dvlasenk@redhat.com> <20150822085453.GB10490@gmail.com> <55D8C61B.3010902@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55D8C61B.3010902@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Denys Vlasenko wrote: > > static FUNC const st_instr_table[64] = { > > - fadd__, fld_i_, fcmovb, fcmovnb, fadd_i, ffree_, faddp_, _df_c0_, > > - fmul__, fxch_i, fcmove, fcmovne, fmul_i, _dd_c8_, fmulp_, _df_c8_, > > - fcom_st, fp_nop, fcmovbe, fcmovnbe, _dc_d0_, fst_i_, _de_d0_, _df_d0_, > > - fcompst, _d9_d8_, fcmovu, fcmovnu, _dc_d8_, fstp_i, fcompp, _df_d8_, > > - fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_, > > - fsubr_, fconst, fucompp, fucomi_, fsub_i, fucomp, fsubp_, fucomip, > > - fdiv__, FPU_triga, __BAD__, fcomi_, fdivri, __BAD__, fdivrp, fcomip, > > - fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__, > > +/* 0x00 */ fadd__, fld_i_, fcmovb, fcmovnb, > > +/* 0x04 */ fadd_i, ffree_, faddp_, _df_c0_, > > +/* 0x08 */ fmul__, fxch_i, fcmove, fcmovne, > > +/* 0x0c */ fmul_i, _dd_c8_, fmulp_, _df_c8_, > > +/* 0x10 */ fcom_st, fp_nop, fcmovbe, fcmovnbe, > > +/* 0x14 */ _dc_d0_, fst_i_, _de_d0_, _df_d0_, > > +/* 0x18 */ fcompst, _d9_d8_, fcmovu, fcmovnu, > > +/* 0x1c */ _dc_d8_, fstp_i, fcompp, _df_d8_, > > +/* 0x20 */ fsub__, FPU_etc, __BAD__, finit_, > > +/* 0x24 */ fsubri, fucom_, fsubrp, fstsw_, > > +/* 0x28 */ fsubr_, fconst, fucompp, fucomi_, > > +/* 0x2c */ fsub_i, fucomp, fsubp_, fucomip, > > +/* 0x30 */ fdiv__, FPU_triga, __BAD__, fcomi_, > > +/* 0x34 */ fdivri, __BAD__, fdivrp, fcomip, > > +/* 0x38 */ fdivr_, FPU_trigb, __BAD__, __BAD__, > > +/* 0x3c */ fdiv_i, __BAD__, fdivp_, __BAD__, > > The numeric comments added at the left don't look correct. Yeah, so they are correct for the purpose I used it: I simply wanted to index the table by its natural index: 'instr_idx', which is derived from the opcode. But you are right that indexing it by the opcode is more useful for future extensions: > In this table, each _column_ corresponds to one 0xd? opcode. > Each row corresponds to a group of mod-reg-rm bytes > with only "rm" field chnaging. (These insns act on registers, > not memory, and "rm" value encodes register number, st(i).) > > Something like this: > > /*Opcode: d8 d9 da db dc dd de df */ > /*c0..7*/ fadd__, fld_i_, fcmovb, fcmovnb, fadd_i, ffree_, faddp_, _df_c0_, > /*c8..f*/ fmul__, fxch_i, fcmove, fcmovne, fmul_i, _dd_c8_,fmulp_, _df_c8_, > /*d0..7*/ fcom_st,fp_nop, fcmovbe,fcmovnbe,_dc_d0_,fst_i_, _de_d0_,_df_d0_, > /*d8..f*/ fcompst,_d9_d8_, fcmovu, fcmovnu, _dc_d8_,fstp_i, fcompp, _df_d8_, > /*e0..7*/ fsub__, FPU_etc, __BAD__,finit_, fsubri, fucom_, fsubrp, fstsw_, > /*e8..f*/ fsubr_, fconst, fucompp,fucomi_, fsub_i, fucomp, fsubp_, fucomip, > /*f0..7*/ fdiv__, FPU_triga,__BAD__,fcomi_, fdivri, __BAD__,fdivrp, fcomip, > /*f8..f*/ fdivr_, FPU_trigb,__BAD__,__BAD__, fdiv_i, __BAD__,fdivp_, __BAD__, (Assuming you also do the table alignment improvements I did, the current format is pretty hard to navigate.) > > > They should be: Hm, your mail seems to have been cut off at this point. Thanks, Ingo