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Tue Jul 14 11:00:16 1998 Alan Modra <alan@spri.levels.unisa.edu.au>

Browse source 
* doc/c-i386.texi: Fix a typo.  Use the term 80-bit real rather
	than temporary real.
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Ian Lance Taylor 1998-07-14 15:01:17 +00:00
parent 4b987239ea
commit 83d0817a9f
2 changed files with 32 additions and 21 deletions
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5
gas/ChangeLog
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@ -1,3 +1,8 @@
Tue Jul 14 11:00:16 1998 Alan Modra <alan@spri.levels.unisa.edu.au>
* doc/c-i386.texi: Fix a typo. Use the term 80-bit real rather
than temporary real.
Mon Jul 13 13:55:42 1998 Ian Lance Taylor <ian@cygnus.com> Mon Jul 13 13:55:42 1998 Ian Lance Taylor <ian@cygnus.com>
* write.c (subsegs_finish): Don't align the segments if there were * write.c (subsegs_finish): Don't align the segments if there were

48
gas/doc/c-i386.texi
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@ -77,7 +77,7 @@ reversed order. @ref{i386-Bugs}.
In AT&T syntax the size of memory operands is determined from the last In AT&T syntax the size of memory operands is determined from the last
character of the opcode name. Opcode suffixes of @samp{b}, @samp{w}, character of the opcode name. Opcode suffixes of @samp{b}, @samp{w},
and @samp{l} specify byte (8-bit), word (16-bit), and long (32-bit) and @samp{l} specify byte (8-bit), word (16-bit), and long (32-bit)
memory references. Intel syntax accomplishes this by prefixes memory memory references. Intel syntax accomplishes this by prefixing memory
operands (@emph{not} the opcodes themselves) with @samp{byte ptr}, operands (@emph{not} the opcodes themselves) with @samp{byte ptr},
@samp{word ptr}, and @samp{dword ptr}. Thus, Intel @samp{mov al, byte @samp{word ptr}, and @samp{dword ptr}. Thus, Intel @samp{mov al, byte
ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T syntax. ptr @var{foo}} is @samp{movb @var{foo}, %al} in AT&T syntax.
@ -215,19 +215,18 @@ to repeat string instructions, to provide section overrides, to perform
bus lock operations, and to give operand and address size (16-bit bus lock operations, and to give operand and address size (16-bit
operands are specified in an instruction by prefixing what would operands are specified in an instruction by prefixing what would
normally be 32-bit operands with a ``operand size'' opcode prefix). normally be 32-bit operands with a ``operand size'' opcode prefix).
Opcode prefixes are usually given as single-line instructions with no Opcode prefixes are best written on the same line as the instruction
operands, and must directly precede the instruction they act upon. For they act upon. For example, the @samp{scas} (scan string) instruction is
example, the @samp{scas} (scan string) instruction is repeated with: repeated with:
@smallexample @smallexample
repne repne scas %es:(%edi),%al
scas
@end smallexample
@noindent
or
@smallexample
repne/scas
@end smallexample @end smallexample
You may also place prefixes on the lines immediately preceding the
opcode, but this circumvents checks that @code{@value{AS}} does with
prefixes, and will not work with all prefixes.
Here is a list of opcode prefixes: Here is a list of opcode prefixes:
@cindex section override prefixes, i386 @cindex section override prefixes, i386
@ -242,7 +241,13 @@ using the @var{section}:@var{memory-operand} form for memory references.
Operand/Address size prefixes @samp{data16} and @samp{addr16} Operand/Address size prefixes @samp{data16} and @samp{addr16}
change 32-bit operands/addresses into 16-bit operands/addresses, change 32-bit operands/addresses into 16-bit operands/addresses,
while @samp{data32} and @samp{addr32} change 16-bit ones (in a while @samp{data32} and @samp{addr32} change 16-bit ones (in a
@code{.code16} section) into 32-bit operands/addresses. @code{.code16} section) into 32-bit operands/addresses. These prefixes
@emph{must} appear on the same line of code as the opcode they modify.
For example, in a 16-bit @code{.code16} section, you might write:
@smallexample
addr32 jmpl *(%ebx)
@end smallexample
@cindex bus lock prefixes, i386 @cindex bus lock prefixes, i386
@cindex inhibiting interrupts, i386 @cindex inhibiting interrupts, i386
@ -289,7 +294,7 @@ to calculate the address of the operand. If no @var{scale} is
specified, @var{scale} is taken to be 1. @var{section} specifies the specified, @var{scale} is taken to be 1. @var{section} specifies the
optional section register for the memory operand, and may override the optional section register for the memory operand, and may override the
default section register (see a 80386 manual for section register default section register (see a 80386 manual for section register
defaults). Note that section overrides in AT&T syntax @emph{must} have defaults). Note that section overrides in AT&T syntax @emph{must}
be preceded by a @samp{%}. If you specify a section override which be preceded by a @samp{%}. If you specify a section override which
coincides with the default section register, @code{@value{AS}} does @emph{not} coincides with the default section register, @code{@value{AS}} does @emph{not}
output any section register override prefixes to assemble the given output any section register override prefixes to assemble the given
@ -376,9 +381,9 @@ types. Constructors build these data types into memory.
Floating point constructors are @samp{.float} or @samp{.single}, Floating point constructors are @samp{.float} or @samp{.single},
@samp{.double}, and @samp{.tfloat} for 32-, 64-, and 80-bit formats. @samp{.double}, and @samp{.tfloat} for 32-, 64-, and 80-bit formats.
These correspond to opcode suffixes @samp{s}, @samp{l}, and @samp{t}. These correspond to opcode suffixes @samp{s}, @samp{l}, and @samp{t}.
@samp{t} stands for temporary real, and that the 80387 only supports @samp{t} stands for 80-bit real. The 80387 only supports this format
this format via the @samp{fldt} (load temporary real to stack top) and via the @samp{fldt} (load 80-bit real to stack top) and @samp{fstpt}
@samp{fstpt} (store temporary real and pop stack) instructions. (store 80-bit real and pop stack) instructions.
@cindex @code{word} directive, i386 @cindex @code{word} directive, i386
@cindex @code{long} directive, i386 @cindex @code{long} directive, i386
@ -386,11 +391,12 @@ this format via the @samp{fldt} (load temporary real to stack top) and
@cindex @code{quad} directive, i386 @cindex @code{quad} directive, i386
@item @item
Integer constructors are @samp{.word}, @samp{.long} or @samp{.int}, and Integer constructors are @samp{.word}, @samp{.long} or @samp{.int}, and
@samp{.quad} for the 16-, 32-, and 64-bit integer formats. The corresponding @samp{.quad} for the 16-, 32-, and 64-bit integer formats. The
opcode suffixes are @samp{s} (single), @samp{l} (long), and @samp{q} corresponding opcode suffixes are @samp{s} (single), @samp{l} (long),
(quad). As with the temporary real format the 64-bit @samp{q} format is and @samp{q} (quad). As with the 80-bit real format, the 64-bit
only present in the @samp{fildq} (load quad integer to stack top) and @samp{q} format is only present in the @samp{fildq} (load quad integer
@samp{fistpq} (store quad integer and pop stack) instructions. to stack top) and @samp{fistpq} (store quad integer and pop stack)
instructions.
@end itemize @end itemize
Register to register operations should not use opcode suffixes. Register to register operations should not use opcode suffixes.