From df256a94d61312ca42865a669594d2b3e7776364 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Thu, 24 Feb 2000 12:40:45 +0000 Subject: [PATCH] Correct intel_syntax fsub* and fdiv* handling. Oh, how I'd like to be rid of UNIXWARE_COMPAT. --- include/opcode/i386.h | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/include/opcode/i386.h b/include/opcode/i386.h index 7bddbed4e..ee7554b0e 100644 --- a/include/opcode/i386.h +++ b/include/opcode/i386.h @@ -23,13 +23,15 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ gcc and possibly many other programs use this reversed syntax, so we're stuck with it. - eg. `fsub %st(3),%st' results in st <- st - st(3) as expected, but - `fsub %st,%st(3)' results in st(3) <- st - st(3), rather than - the expected st(3) <- st(3) - st ! + eg. `fsub %st(3),%st' results in st = st - st(3) as expected, but + `fsub %st,%st(3)' results in st(3) = st - st(3), rather than + the expected st(3) = st(3) - st This happens with all the non-commutative arithmetic floating point operations with two register operands, where the source register is - %st, and destination register is %st(i). Look for FloatDR below. */ + %st, and destination register is %st(i). See FloatDR below. + + The affected opcode map is dceX, dcfX, deeX, defX. */ #ifndef UNIXWARE_COMPAT /* Set non-zero for broken, compatible instructions. Set to zero for @@ -64,6 +66,9 @@ static const template i386_optab[] = { #define sld_FP (sld_Suf|IgnoreSize) #define sldx_FP (sldx_Suf|IgnoreSize) #if UNIXWARE_COMPAT +/* Someone forgot that the FloatR bit reverses the operation when not + equal to the FloatD bit. ie. Changing only FloatD results in the + destination being swapped *and* the direction being reversed. */ #define FloatDR FloatD #else #define FloatDR (FloatD|FloatR)