prefixes.
Enabled by default.
+\b \i\c{bnd} warns about ineffective use of the \c{BND} prefix when a relaxed
+form of jmp instruction becomes jmp short form.
+Enabled by default.
+
\b \i\c{error} causes warnings to be treated as errors. Disabled by
default.
You will need the version number if you report a bug.
+For command-line compatibility with Yasm, the form \i\c{--v} is also
+accepted for this option.
+
\S{opt-y} The \i\c{-y} Option: Display Available Debug Info Formats
Typing \c{nasm -f <option> -y} will display a list of the available
The instruction field may contain any machine instruction: Pentium
and P6 instructions, FPU instructions, MMX instructions and even
undocumented instructions are all supported. The instruction may be
-prefixed by \c{LOCK}, \c{REP}, \c{REPE}/\c{REPZ} or
-\c{REPNE}/\c{REPNZ}, in the usual way. Explicit \I{address-size
-prefixes}address-size and \i{operand-size prefixes} \i\c{A16},
+prefixed by \c{LOCK}, \c{REP}, \c{REPE}/\c{REPZ}, \c{REPNE}/\c{REPNZ},
+\c{XACQUIRE}/\c{XRELEASE} or \c{BND}/\c{NOBND}, in the usual way. Explicit
+\I{address-size prefixes}address-size and \i{operand-size prefixes} \i\c{A16},
\i\c{A32}, \i\c{A64}, \i\c{O16} and \i\c{O32}, \i\c{O64} are provided - one example of their use
is given in \k{mixsize}. You can also use the name of a \I{segment
override}segment register as an instruction prefix: coding
fact, it will also split \c{[eax*2+offset]} into
\c{[eax+eax+offset]}. You can combat this behaviour by the use of
the \c{NOSPLIT} keyword: \c{[nosplit eax*2]} will force
-\c{[eax*2+0]} to be generated literally.
+\c{[eax*2+0]} to be generated literally. \c{[nosplit eax*1]} also has the
+same effect. In another way, a split EA form \c{[0, eax*2]} can be used, too.
+However, \c{NOSPLIT} in \c{[nosplit eax+eax]} will be ignored because user's
+intention here is considered as \c{[eax+eax]}.
In 64-bit mode, NASM will by default generate absolute addresses. The
\i\c{REL} keyword makes it produce \c{RIP}-relative addresses. Since
this is frequently the normally desired behaviour, see the \c{DEFAULT}
directive (\k{default}). The keyword \i\c{ABS} overrides \i\c{REL}.
+A new form of split effective addres syntax is also supported. This is
+mainly intended for mib operands as used by MPX instructions, but can
+be used for any memory reference. The basic concept of this form is
+splitting base and index.
+
+\c mov eax,[ebx+8,ecx*4] ; ebx=base, ecx=index, 4=scale, 8=disp
+
+For mib operands, there are several ways of writing effective address depending
+on the tools. NASM supports all currently possible ways of mib syntax:
+
+\c ; bndstx
+\c ; next 5 lines are parsed same
+\c ; base=rax, index=rbx, scale=1, displacement=3
+\c bndstx [rax+0x3,rbx], bnd0 ; NASM - split EA
+\c bndstx [rbx*1+rax+0x3], bnd0 ; GAS - '*1' indecates an index reg
+\c bndstx [rax+rbx+3], bnd0 ; GAS - without hints
+\c bndstx [rax+0x3], bnd0, rbx ; ICC-1
+\c bndstx [rax+0x3], rbx, bnd0 ; ICC-2
+
+When broadcasting decorator is used, the opsize keyword should match
+the size of each element.
+
+\c VDIVPS zmm4, zmm5, dword [rbx]{1to16} ; single-precision float
+\c VDIVPS zmm4, zmm5, zword [rbx] ; packed 512 bit memory
+
\H{const} \i{Constants}
obnoxious, as the explicit form is pretty much the only one one wishes
to use.
-Currently, the only \c{DEFAULT} that is settable is whether or not
-registerless instructions in 64-bit mode are \c{RIP}-relative or not.
-By default, they are absolute unless overridden with the \i\c{REL}
+Currently, \c{DEFAULT} can set \c{REL} & \c{ABS} and \c{BND} & \c{NOBND}.
+
+\S{REL & ABS} \i\c{REL} & \i\c{ABS}: RIP-relative addressing
+
+This sets whether registerless instructions in 64-bit mode are \c{RIP}-relative
+or not. By default, they are absolute unless overridden with the \i\c{REL}
specifier (see \k{effaddr}). However, if \c{DEFAULT REL} is
specified, \c{REL} is default, unless overridden with the \c{ABS}
specifier, \e{except when used with an FS or GS segment override}.
\c{DEFAULT REL} is disabled with \c{DEFAULT ABS}.
+\S{BND & NOBND} \i\c{BND} & \i\c{NOBND}: \c{BND} prefix
+
+If \c{DEFAULT BND} is set, all bnd-prefix available instructions following
+this directive are prefixed with bnd. To override it, \c{NOBND} prefix can
+be used.
+
+\c DEFAULT BND
+\c call foo ; BND will be prefixed
+\c nobnd call foo ; BND will NOT be prefixed
+
+\c{DEFAULT NOBND} can disable \c{DEFAULT BND} and then \c{BND} prefix will be
+added only when explicitly specified in code.
+
+\c{DEFAULT BND} is expected to be the normal configuration for writing
+MPX-enabled code.
+
\H{section} \i\c{SECTION} or \i\c{SEGMENT}: Changing and \i{Defining
Sections}
projects / platform / upstream / nasm.git / blobdiff