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FR 2499968: structures with non-zero base offset

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Add an optional second argument to struc, document it and test it.
Also removed trailing whitespace in nasmdoc.src in the process.
This commit is contained in:
Victor van den Elzen
2009-03-27 03:53:59 +01:00
parent 1d7d7c64cf
commit 56b820355c
3 changed files with 119 additions and 64 deletions
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140
doc/nasmdoc.src
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@@ -511,10 +511,10 @@ right. For example:
\c nasm -f elf myfile.asm -l myfile.lst \c nasm -f elf myfile.asm -l myfile.lst
If a list file is selected, you may turn off listing for a If a list file is selected, you may turn off listing for a
section of your source with \c{[list -]}, and turn it back on section of your source with \c{[list -]}, and turn it back on
with \c{[list +]}, (the default, obviously). There is no "user with \c{[list +]}, (the default, obviously). There is no "user
form" (without the brackets). This can be used to list only form" (without the brackets). This can be used to list only
sections of interest, avoiding excessively long listings. sections of interest, avoiding excessively long listings.
@@ -589,7 +589,7 @@ A complete list of the available debug file formats for an output
format can be seen by issuing the command \c{nasm -f <format> -y}. Not format can be seen by issuing the command \c{nasm -f <format> -y}. Not
all output formats currently support debugging output. See \k{opt-y}. all output formats currently support debugging output. See \k{opt-y}.
This should not be confused with the \c{-f dbg} output format option which This should not be confused with the \c{-f dbg} output format option which
is not built into NASM by default. For information on how is not built into NASM by default. For information on how
to enable it when building from the sources, see \k{dbgfmt}. to enable it when building from the sources, see \k{dbgfmt}.
@@ -597,25 +597,25 @@ to enable it when building from the sources, see \k{dbgfmt}.
\S{opt-g} The \i\c{-g} Option: Enabling \i{Debug Information}. \S{opt-g} The \i\c{-g} Option: Enabling \i{Debug Information}.
This option can be used to generate debugging information in the specified This option can be used to generate debugging information in the specified
format. See \k{opt-F}. Using \c{-g} without \c{-F} results in emitting format. See \k{opt-F}. Using \c{-g} without \c{-F} results in emitting
debug info in the default format, if any, for the selected output format. debug info in the default format, if any, for the selected output format.
If no debug information is currently implemented in the selected output If no debug information is currently implemented in the selected output
format, \c{-g} is \e{silently ignored}. format, \c{-g} is \e{silently ignored}.
\S{opt-X} The \i\c{-X} Option: Selecting an \i{Error Reporting Format} \S{opt-X} The \i\c{-X} Option: Selecting an \i{Error Reporting Format}
This option can be used to select an error reporting format for any This option can be used to select an error reporting format for any
error messages that might be produced by NASM. error messages that might be produced by NASM.
Currently, two error reporting formats may be selected. They are Currently, two error reporting formats may be selected. They are
the \c{-Xvc} option and the \c{-Xgnu} option. The GNU format is the \c{-Xvc} option and the \c{-Xgnu} option. The GNU format is
the default and looks like this: the default and looks like this:
\c filename.asm:65: error: specific error message \c filename.asm:65: error: specific error message
where \c{filename.asm} is the name of the source file in which the where \c{filename.asm} is the name of the source file in which the
error was detected, \c{65} is the source file line number on which error was detected, \c{65} is the source file line number on which
the error was detected, \c{error} is the severity of the error (this the error was detected, \c{error} is the severity of the error (this
could be \c{warning}), and \c{specific error message} is a more could be \c{warning}), and \c{specific error message} is a more
detailed text message which should help pinpoint the exact problem. detailed text message which should help pinpoint the exact problem.
@@ -626,7 +626,7 @@ Visual C++ and some other programs. It looks like this:
\c filename.asm(65) : error: specific error message \c filename.asm(65) : error: specific error message
where the only difference is that the line number is in parentheses where the only difference is that the line number is in parentheses
instead of being delimited by colons. instead of being delimited by colons.
See also the \c{Visual C++} output format, \k{win32fmt}. See also the \c{Visual C++} output format, \k{win32fmt}.
@@ -787,7 +787,7 @@ with a \i{stub preprocessor} which does nothing.
NASM defaults to not optimizing operands which can fit into a signed byte. NASM defaults to not optimizing operands which can fit into a signed byte.
This means that if you want the shortest possible object code, This means that if you want the shortest possible object code,
you have to enable optimization. you have to enable optimization.
Using the \c{-O} option, you can tell NASM to carry out different Using the \c{-O} option, you can tell NASM to carry out different
levels of optimization. The syntax is: levels of optimization. The syntax is:
@@ -856,7 +856,7 @@ being invoked with the wrong number of parameters. This warning
class is enabled by default; see \k{mlmacover} for an example of why class is enabled by default; see \k{mlmacover} for an example of why
you might want to disable it. you might want to disable it.
\b \i\c{macro-selfref} warns if a macro references itself. This \b \i\c{macro-selfref} warns if a macro references itself. This
warning class is disabled by default. warning class is disabled by default.
\b\i\c{macro-defaults} warns when a macro has more default \b\i\c{macro-defaults} warns when a macro has more default
@@ -871,8 +871,8 @@ see \k{syntax} for more information.
\b \i\c{number-overflow} covers warnings about numeric constants which \b \i\c{number-overflow} covers warnings about numeric constants which
don't fit in 64 bits. This warning class is enabled by default. don't fit in 64 bits. This warning class is enabled by default.
\b \i\c{gnu-elf-extensions} warns if 8-bit or 16-bit relocations \b \i\c{gnu-elf-extensions} warns if 8-bit or 16-bit relocations
are used in \c{-f elf} format. The GNU extensions allow this. are used in \c{-f elf} format. The GNU extensions allow this.
This warning class is disabled by default. This warning class is disabled by default.
\b \i\c{float-overflow} warns about floating point overflow. \b \i\c{float-overflow} warns about floating point overflow.
@@ -916,8 +916,8 @@ You will need the version number if you report a bug.
\S{opt-y} The \i\c{-y} Option: Display Available Debug Info Formats \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 Typing \c{nasm -f <option> -y} will display a list of the available
debug info formats for the given output format. The default format debug info formats for the given output format. The default format
is indicated by an asterisk. For example: is indicated by an asterisk. For example:
\c nasm -f elf -y \c nasm -f elf -y
@@ -930,10 +930,10 @@ is indicated by an asterisk. For example:
\S{opt-pfix} The \i\c{--prefix} and \i\c{--postfix} Options. \S{opt-pfix} The \i\c{--prefix} and \i\c{--postfix} Options.
The \c{--prefix} and \c{--postfix} options prepend or append The \c{--prefix} and \c{--postfix} options prepend or append
(respectively) the given argument to all \c{global} or (respectively) the given argument to all \c{global} or
\c{extern} variables. E.g. \c{--prefix _} will prepend the \c{extern} variables. E.g. \c{--prefix _} will prepend the
underscore to all global and external variables, as C sometimes underscore to all global and external variables, as C sometimes
(but not always) likes it. (but not always) likes it.
@@ -1141,7 +1141,7 @@ An identifier may also be prefixed with a \I{$, prefix}\c{$} to
indicate that it is intended to be read as an identifier and not a indicate that it is intended to be read as an identifier and not a
reserved word; thus, if some other module you are linking with reserved word; thus, if some other module you are linking with
defines a symbol called \c{eax}, you can refer to \c{$eax} in NASM defines a symbol called \c{eax}, you can refer to \c{$eax} in NASM
code to distinguish the symbol from the register. Maximum length of code to distinguish the symbol from the register. Maximum length of
an identifier is 4095 characters. an identifier is 4095 characters.
The instruction field may contain any machine instruction: Pentium The instruction field may contain any machine instruction: Pentium
@@ -1541,7 +1541,7 @@ For example:
\c{__utf16__} and \c{__utf32__} can be applied either to strings \c{__utf16__} and \c{__utf32__} can be applied either to strings
passed to the \c{DB} family instructions, or to character constants in passed to the \c{DB} family instructions, or to character constants in
an expression context. an expression context.
\S{fltconst} \I{floating-point, constants}Floating-Point Constants \S{fltconst} \I{floating-point, constants}Floating-Point Constants
@@ -2051,7 +2051,7 @@ where macro expansion would otherwise not occur, including in the
names other macros. For example, if you have a set of macros named names other macros. For example, if you have a set of macros named
\c{Foo16}, \c{Foo32} and \c{Foo64}, you could write: \c{Foo16}, \c{Foo32} and \c{Foo64}, you could write:
\c mov ax,Foo%[__BITS__] ; The Foo value \c mov ax,Foo%[__BITS__] ; The Foo value
to use the builtin macro \c{__BITS__} (see \k{bitsm}) to automatically to use the builtin macro \c{__BITS__} (see \k{bitsm}) to automatically
select between them. Similarly, the two statements: select between them. Similarly, the two statements:
@@ -3043,7 +3043,7 @@ be gradually used up and other applications to start crashing.
These commands allow you to split your sources into multiple files. These commands allow you to split your sources into multiple files.
\S{include} \i\c{%include}: \i{Including Other Files} \S{include} \i\c{%include}: \i{Including Other Files}
Using, once again, a very similar syntax to the C preprocessor, Using, once again, a very similar syntax to the C preprocessor,
NASM's preprocessor lets you include other source files into your NASM's preprocessor lets you include other source files into your
@@ -3742,13 +3742,15 @@ structures; instead, the preprocessor is sufficiently powerful that
data structures can be implemented as a set of macros. The macros data structures can be implemented as a set of macros. The macros
\c{STRUC} and \c{ENDSTRUC} are used to define a structure data type. \c{STRUC} and \c{ENDSTRUC} are used to define a structure data type.
\c{STRUC} takes one parameter, which is the name of the data type. \c{STRUC} takes one or two parameters. The first parameter is the name
This name is defined as a symbol with the value zero, and also has of the data type. The second, optional parameter is the base offset of
the suffix \c{_size} appended to it and is then defined as an the structure. The name of the data type is defined as a symbol with
\c{EQU} giving the size of the structure. Once \c{STRUC} has been the value of the base offset, and the name of the data type with the
issued, you are defining the structure, and should define fields suffix \c{_size} appended to it is defined as an \c{EQU} giving the
using the \c{RESB} family of pseudo-instructions, and then invoke size of the structure. Once \c{STRUC} has been issued, you are
\c{ENDSTRUC} to finish the definition. defining the structure, and should define fields using the \c{RESB}
family of pseudo-instructions, and then invoke \c{ENDSTRUC} to finish
the definition.
For example, to define a structure called \c{mytype} containing a For example, to define a structure called \c{mytype} containing a
longword, a word, a byte and a string of bytes, you might code longword, a word, a byte and a string of bytes, you might code
@@ -3767,8 +3769,8 @@ from the beginning of a \c{mytype} structure to the longword field),
\c{mt_word} as 4, \c{mt_byte} as 6, \c{mt_str} as 7, \c{mytype_size} \c{mt_word} as 4, \c{mt_byte} as 6, \c{mt_str} as 7, \c{mytype_size}
as 39, and \c{mytype} itself as zero. as 39, and \c{mytype} itself as zero.
The reason why the structure type name is defined at zero is a side The reason why the structure type name is defined at zero by default
effect of allowing structures to work with the local label is a side effect of allowing structures to work with the local label
mechanism: if your structure members tend to have the same names in mechanism: if your structure members tend to have the same names in
more than one structure, you can define the above structure like this: more than one structure, you can define the above structure like this:
@@ -3792,6 +3794,26 @@ so code such as \c{mov ax,[mystruc.mt_word]} is not valid.
correct syntax is \c{mov ax,[mystruc+mt_word]} or \c{mov correct syntax is \c{mov ax,[mystruc+mt_word]} or \c{mov
ax,[mystruc+mytype.word]}. ax,[mystruc+mytype.word]}.
Sometimes you only have the address of the structure displaced by an
offset. For example, consider this standard stack frame setup:
\c push ebp
\c mov ebp, esp
\c sub esp, 40
In this case, you could access an element by subtracting the offset:
\c mov [ebp - 40 + mytype.word], ax
However, if you do not want to repeat this offset, you can use -40 as
a base offset:
\c struc mytype, -40
And access an element this way:
\c mov [ebp + mytype.word], ax
\S{istruc} \i\c{ISTRUC}, \i\c{AT} and \i\c{IEND}: Declaring \S{istruc} \i\c{ISTRUC}, \i\c{AT} and \i\c{IEND}: Declaring
\i{Instances of Structures} \i{Instances of Structures}
@@ -4458,52 +4480,52 @@ bin}\I{segment alignment, in bin}\I{alignment, in bin sections}
\S{multisec} \i\c{Multisection}\I{bin, multisection} support for the BIN format. \S{multisec} \i\c{Multisection}\I{bin, multisection} support for the BIN format.
The \c{bin} format allows the use of multiple sections, of arbitrary names, The \c{bin} format allows the use of multiple sections, of arbitrary names,
besides the "known" \c{.text}, \c{.data}, and \c{.bss} names. besides the "known" \c{.text}, \c{.data}, and \c{.bss} names.
\b Sections may be designated \i\c{progbits} or \i\c{nobits}. Default \b Sections may be designated \i\c{progbits} or \i\c{nobits}. Default
is \c{progbits} (except \c{.bss}, which defaults to \c{nobits}, is \c{progbits} (except \c{.bss}, which defaults to \c{nobits},
of course). of course).
\b Sections can be aligned at a specified boundary following the previous \b Sections can be aligned at a specified boundary following the previous
section with \c{align=}, or at an arbitrary byte-granular position with section with \c{align=}, or at an arbitrary byte-granular position with
\i\c{start=}. \i\c{start=}.
\b Sections can be given a virtual start address, which will be used \b Sections can be given a virtual start address, which will be used
for the calculation of all memory references within that section for the calculation of all memory references within that section
with \i\c{vstart=}. with \i\c{vstart=}.
\b Sections can be ordered using \i\c{follows=}\c{<section>} or \b Sections can be ordered using \i\c{follows=}\c{<section>} or
\i\c{vfollows=}\c{<section>} as an alternative to specifying an explicit \i\c{vfollows=}\c{<section>} as an alternative to specifying an explicit
start address. start address.
\b Arguments to \c{org}, \c{start}, \c{vstart}, and \c{align=} are \b Arguments to \c{org}, \c{start}, \c{vstart}, and \c{align=} are
critical expressions. See \k{crit}. E.g. \c{align=(1 << ALIGN_SHIFT)} critical expressions. See \k{crit}. E.g. \c{align=(1 << ALIGN_SHIFT)}
- \c{ALIGN_SHIFT} must be defined before it is used here. - \c{ALIGN_SHIFT} must be defined before it is used here.
\b Any code which comes before an explicit \c{SECTION} directive \b Any code which comes before an explicit \c{SECTION} directive
is directed by default into the \c{.text} section. is directed by default into the \c{.text} section.
\b If an \c{ORG} statement is not given, \c{ORG 0} is used \b If an \c{ORG} statement is not given, \c{ORG 0} is used
by default. by default.
\b The \c{.bss} section will be placed after the last \c{progbits} \b The \c{.bss} section will be placed after the last \c{progbits}
section, unless \c{start=}, \c{vstart=}, \c{follows=}, or \c{vfollows=} section, unless \c{start=}, \c{vstart=}, \c{follows=}, or \c{vfollows=}
has been specified. has been specified.
\b All sections are aligned on dword boundaries, unless a different \b All sections are aligned on dword boundaries, unless a different
alignment has been specified. alignment has been specified.
\b Sections may not overlap. \b Sections may not overlap.
\b NASM creates the \c{section.<secname>.start} for each section, \b NASM creates the \c{section.<secname>.start} for each section,
which may be used in your code. which may be used in your code.
\S{map}\i{Map files} \S{map}\i{Map files}
Map files can be generated in \c{-f bin} format by means of the \c{[map]} Map files can be generated in \c{-f bin} format by means of the \c{[map]}
option. Map types of \c{all} (default), \c{brief}, \c{sections}, \c{segments}, option. Map types of \c{all} (default), \c{brief}, \c{sections}, \c{segments},
or \c{symbols} may be specified. Output may be directed to \c{stdout} or \c{symbols} may be specified. Output may be directed to \c{stdout}
(default), \c{stderr}, or a specified file. E.g. (default), \c{stderr}, or a specified file. E.g.
\c{[map symbols myfile.map]}. No "user form" exists, the square \c{[map symbols myfile.map]}. No "user form" exists, the square
brackets must be used. brackets must be used.
@@ -4951,7 +4973,7 @@ still be perfectly possible.
Registering custom exception handler on the other hand requires certain Registering custom exception handler on the other hand requires certain
"magic." As of version 2.03 additional directive is implemented, "magic." As of version 2.03 additional directive is implemented,
\c{safeseh}, which instructs the assembler to produce appropriately \c{safeseh}, which instructs the assembler to produce appropriately
formatted input data for above mentioned "safe exception handler formatted input data for above mentioned "safe exception handler
table." Its typical use would be: table." Its typical use would be:
\c section .text \c section .text
@@ -4980,14 +5002,14 @@ table." Its typical use would be:
\c ret \c ret
\c text: db 'OK to rethrow, CANCEL to generate core dump',0 \c text: db 'OK to rethrow, CANCEL to generate core dump',0
\c caption:db 'SEGV',0 \c caption:db 'SEGV',0
\c \c
\c section .drectve info \c section .drectve info
\c db '/defaultlib:user32.lib /defaultlib:msvcrt.lib ' \c db '/defaultlib:user32.lib /defaultlib:msvcrt.lib '
As you might imagine, it's perfectly possible to produce .exe binary As you might imagine, it's perfectly possible to produce .exe binary
with "safe exception handler table" and yet engage unregistered with "safe exception handler table" and yet engage unregistered
exception handler. Indeed, handler is engaged by simply manipulating exception handler. Indeed, handler is engaged by simply manipulating
\c{[fs:0]} location at run-time, something linker has no power over, \c{[fs:0]} location at run-time, something linker has no power over,
run-time that is. It should be explicitly mentioned that such failure run-time that is. It should be explicitly mentioned that such failure
to register handler's entry point with \c{safeseh} directive has to register handler's entry point with \c{safeseh} directive has
undesired side effect at run-time. If exception is raised and undesired side effect at run-time. If exception is raised and
@@ -5007,7 +5029,7 @@ later can still be linked by earlier versions or non-Microsoft linkers.
\H{win64fmt} \i\c{win64}: Microsoft Win64 Object Files \H{win64fmt} \i\c{win64}: Microsoft Win64 Object Files
The \c{win64} output format generates Microsoft Win64 object files, The \c{win64} output format generates Microsoft Win64 object files,
which is nearly 100% identical to the \c{win32} object format (\k{win32fmt}) which is nearly 100% identical to the \c{win32} object format (\k{win32fmt})
with the exception that it is meant to target 64-bit code and the x86-64 with the exception that it is meant to target 64-bit code and the x86-64
platform altogether. This object file is used exactly the same as the \c{win32} platform altogether. This object file is used exactly the same as the \c{win32}
@@ -5165,7 +5187,7 @@ leaf function:
\c main_end: \c main_end:
\c text: db 'OK to rethrow, CANCEL to generate core dump',0 \c text: db 'OK to rethrow, CANCEL to generate core dump',0
\c caption:db 'SEGV',0 \c caption:db 'SEGV',0
\c \c
\c section .pdata rdata align=4 \c section .pdata rdata align=4
\c dd main wrt ..imagebase \c dd main wrt ..imagebase
\c dd main_end wrt ..imagebase \c dd main_end wrt ..imagebase
@@ -5245,7 +5267,7 @@ custom language-specific exception handler would look like this:
\c context->R15 = rsp[-1]; \c context->R15 = rsp[-1];
\c } \c }
\c context->Rsp = (ULONG64)rsp; \c context->Rsp = (ULONG64)rsp;
\c \c
\c memcpy (disp->ContextRecord,context,sizeof(CONTEXT)); \c memcpy (disp->ContextRecord,context,sizeof(CONTEXT));
\c RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase, \c RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase,
\c dips->ControlPc,disp->FunctionEntry,disp->ContextRecord, \c dips->ControlPc,disp->FunctionEntry,disp->ContextRecord,
@@ -5641,7 +5663,7 @@ or \i\c{object} to the directive:
\S{rdfimpt} \c{rdf} Extensions to the \c{EXTERN} directive\I{EXTERN, \S{rdfimpt} \c{rdf} Extensions to the \c{EXTERN} directive\I{EXTERN,
rdf extensions to} rdf extensions to}
By default the \c{EXTERN} directive in \c{RDOFF} declares a "pure external" By default the \c{EXTERN} directive in \c{RDOFF} declares a "pure external"
symbol (i.e. the static linker will complain if such a symbol is not resolved). symbol (i.e. the static linker will complain if such a symbol is not resolved).
To declare an "imported" symbol, which must be resolved later during a dynamic To declare an "imported" symbol, which must be resolved later during a dynamic
linking phase, \c{RDOFF} offers an additional \c{import} modifier. As in linking phase, \c{RDOFF} offers an additional \c{import} modifier. As in

10
standard.mac
View File

@@ -39,14 +39,14 @@
__SECT__ __SECT__
%endmacro %endmacro
%imacro struc 1.nolist %imacro struc 1-2.nolist 0
%push %push
%define %$strucname %1 %define %$strucname %1
[absolute 0] [absolute %2]
%$strucname: ; allow definition of `.member' to work sanely %$strucname: ; allow definition of `.member' to work sanely
%endmacro %endmacro
%imacro endstruc 0.nolist %imacro endstruc 0.nolist
%{$strucname}_size: %{$strucname}_size equ ($-%$strucname)
%pop %pop
__SECT__ __SECT__
%endmacro %endmacro
@@ -57,7 +57,7 @@ __SECT__
%$strucstart: %$strucstart:
%endmacro %endmacro
%imacro at 1-2+.nolist %imacro at 1-2+.nolist
times %1-($-%$strucstart) db 0 times (%1-%$strucname)-($-%$strucstart) db 0
%2 %2
%endmacro %endmacro
%imacro iend 0.nolist %imacro iend 0.nolist

33
test/struc.asm Normal file
View File

@@ -0,0 +1,33 @@
;Testname=test; Arguments=-fbin -ostruc.bin; Files=stdout stderr struc.bin
bits 32
; Simple struc example
struc teststruc1
.long: resd 1
.word: resw 1
.byte: resb 1
.str: resb 32
endstruc
; Reference with offset
mov [ebp - 40 + teststruc1.word], ax
istruc teststruc1
at .word, db 5
iend
; Struc with base offset
; should be the same as the previous stuc
struc teststruc2, -40
.long: resd 1
.word: resw 1
.byte: resb 1
.str: resb 32
endstruc
mov [ebp + teststruc2.word], ax
istruc teststruc2
at .word, db 5
iend