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diff --git a/StdLib/LibC/Softfloat/softfloat-source.txt b/StdLib/LibC/Softfloat/softfloat-source.txt deleted file mode 100644 index e77f77a1d0..0000000000 --- a/StdLib/LibC/Softfloat/softfloat-source.txt +++ /dev/null @@ -1,383 +0,0 @@ -$NetBSD: softfloat-source.txt,v 1.2 2006/11/24 19:46:58 christos Exp $
-
-SoftFloat Release 2a Source Documentation
-
-John R. Hauser
-1998 December 14
-
-
--------------------------------------------------------------------------------
-Introduction
-
-SoftFloat is a software implementation of floating-point that conforms to
-the IEC/IEEE Standard for Binary Floating-Point Arithmetic. SoftFloat can
-support four floating-point formats: single precision, double precision,
-extended double precision, and quadruple precision. All operations required
-by the IEEE Standard are implemented, except for conversions to and from
-decimal. SoftFloat is distributed in the form of C source code, so a
-C compiler is needed to compile the code. Support for the extended double-
-precision and quadruple-precision formats is dependent on the C compiler
-implementing a 64-bit integer type.
-
-This document gives information needed for compiling and/or porting
-SoftFloat.
-
-The source code for SoftFloat is intended to be relatively machine-
-independent and should be compilable using any ISO/ANSI C compiler. At the
-time of this writing, SoftFloat has been successfully compiled with the GNU
-C Compiler (`gcc') for several platforms.
-
-
--------------------------------------------------------------------------------
-Limitations
-
-SoftFloat as written requires an ISO/ANSI-style C compiler. No attempt has
-been made to accommodate compilers that are not ISO-conformant. Older ``K&R-
-style'' compilers are not adequate for compiling SoftFloat. All testing I
-have done so far has been with the GNU C Compiler. Compilation with other
-compilers should be possible but has not been tested.
-
-The SoftFloat sources assume that source code file names can be longer than
-8 characters. In order to compile under an MS-DOS-type system, many of the
-source files will need to be renamed, and the source and makefiles edited
-appropriately. Once compiled, the SoftFloat binary does not depend on the
-existence of long file names.
-
-The underlying machine is assumed to be binary with a word size that is a
-power of 2. Bytes are 8 bits. Support for the extended double-precision
-and quadruple-precision formats depends on the C compiler implementing
-a 64-bit integer type. If the largest integer type supported by the
-C compiler is 32 bits, SoftFloat is limited to the single- and double-
-precision formats.
-
-
--------------------------------------------------------------------------------
-Contents
-
- Introduction
- Limitations
- Contents
- Legal Notice
- SoftFloat Source Directory Structure
- SoftFloat Source Files
- processors/*.h
- softfloat/bits*/*/softfloat.h
- softfloat/bits*/*/milieu.h
- softfloat/bits*/*/softfloat-specialize
- softfloat/bits*/softfloat-macros
- softfloat/bits*/softfloat.c
- Steps to Creating a `softfloat.o'
- Making `softfloat.o' a Library
- Testing SoftFloat
- Timing SoftFloat
- Compiler Options and Efficiency
- Processor-Specific Optimization of `softfloat.c' Using `softfloat-macros'
- Contact Information
-
-
-
--------------------------------------------------------------------------------
-Legal Notice
-
-SoftFloat was written by John R. Hauser. This work was made possible in
-part by the International Computer Science Institute, located at Suite 600,
-1947 Center Street, Berkeley, California 94704. Funding was partially
-provided by the National Science Foundation under grant MIP-9311980. The
-original version of this code was written as part of a project to build
-a fixed-point vector processor in collaboration with the University of
-California at Berkeley, overseen by Profs. Nelson Morgan and John Wawrzynek.
-
-THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
-has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
-TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
-PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
-AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
-
-
--------------------------------------------------------------------------------
-SoftFloat Source Directory Structure
-
-Because SoftFloat is targeted to multiple platforms, its source code
-is slightly scattered between target-specific and target-independent
-directories and files. The directory structure is as follows:
-
- processors
- softfloat
- bits64
- templates
- 386-Win32-gcc
- SPARC-Solaris-gcc
- bits32
- templates
- 386-Win32-gcc
- SPARC-Solaris-gcc
-
-The two topmost directories and their contents are:
-
- softfloat - Most of the source code needed for SoftFloat.
- processors - Target-specific header files that are not specific to
- SoftFloat.
-
-The `softfloat' directory is further split into two parts:
-
- bits64 - SoftFloat implementation using 64-bit integers.
- bits32 - SoftFloat implementation using only 32-bit integers.
-
-Within these directories are subdirectories for each of the targeted
-platforms. The SoftFloat source code is distributed with targets
-`386-Win32-gcc' and `SPARC-Solaris-gcc' (and perhaps others) already
-prepared for both the 32-bit and 64-bit implementations. Source files that
-are not within these target-specific subdirectories are intended to be
-target-independent.
-
-The naming convention used for the target-specific directories is
-`<processor>-<executable-type>-<compiler>'. The names of the supplied
-target directories should be interpreted as follows:
-
- <processor>:
- 386 - Intel 386-compatible processor.
- SPARC - SPARC processor (as used by Sun machines).
- <executable-type>:
- Win32 - Microsoft Win32 executable.
- Solaris - Sun Solaris executable.
- <compiler>:
- gcc - GNU C Compiler.
-
-You do not need to maintain this convention if you do not want to.
-
-Alongside the supplied target-specific directories is a `templates'
-directory containing a set of ``generic'' target-specific source files. A
-new target directory can be created by copying the `templates' directory and
-editing the files inside. (Complete instructions for porting SoftFloat to a
-new target are in the section _Steps_to_Creating_a_`softfloat.o'_.) Note
-that the `templates' directory will not work as a target directory without
-some editing. To avoid confusion, it would be wise to refrain from editing
-the files inside `templates' directly.
-
-
--------------------------------------------------------------------------------
-SoftFloat Source Files
-
-The purpose of each source file is described below. In the following,
-the `*' symbol is used in place of the name of a specific target, such as
-`386-Win32-gcc' or `SPARC-Solaris-gcc', or in place of some other text, as
-in `bits*' for either `bits32' or `bits64'.
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-processors/*.h
-
-The target-specific `processors' header file defines integer types
-of various sizes, and also defines certain C preprocessor macros that
-characterize the target. The two examples supplied are `386-gcc.h' and
-`SPARC-gcc.h'. The naming convention used for processor header files is
-`<processor>-<compiler>.h'.
-
-If 64-bit integers are supported by the compiler, the macro name `BITS64'
-should be defined here along with the corresponding 64-bit integer
-types. In addition, the function-like macro `LIT64' must be defined for
-constructing 64-bit integer literals (constants). The `LIT64' macro is used
-consistently in the SoftFloat code to annotate 64-bit literals.
-
-If `BITS64' is not defined, only the 32-bit version of SoftFloat can be
-compiled. If `BITS64' _is_ defined, either can be compiled.
-
-If an inlining attribute (such as an `inline' keyword) is provided by the
-compiler, the macro `INLINE' should be defined to the appropriate keyword.
-If not, `INLINE' can be set to the keyword `static'. The `INLINE' macro
-appears in the SoftFloat source code before every function that should
-be inlined by the compiler. SoftFloat depends on inlining to obtain
-good speed. Even if inlining cannot be forced with a language keyword,
-the compiler may still be able to perform inlining on its own as an
-optimization. If a command-line option is needed to convince the compiler
-to perform this optimization, this should be assured in the makefile. (See
-the section _Compiler_Options_and_Efficiency_ below.)
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-softfloat/bits*/*/softfloat.h
-
-The target-specific `softfloat.h' header file defines the SoftFloat
-interface as seen by clients.
-
-Unlike the actual function definitions in `softfloat.c', the declarations
-in `softfloat.h' do not use any of the types defined by the `processors'
-header file. This is done so that clients will not have to include the
-`processors' header file in order to use SoftFloat. Nevertheless, the
-target-specific declarations in `softfloat.h' must match what `softfloat.c'
-expects. For example, if `int32' is defined as `int' in the `processors'
-header file, then in `softfloat.h' the output of `float32_to_int32' should
-be stated as `int', although in `softfloat.c' it is given in target-
-independent form as `int32'.
-
-For the `bits64' implementation of SoftFloat, the macro names `FLOATX80' and
-`FLOAT128' must be defined in order for the extended double-precision and
-quadruple-precision formats to be enabled in the code. Conversely, either
-or both of the extended formats can be disabled by simply removing the
-`#define' of the respective macro. When an extended format is not enabled,
-none of the functions that either input or output the format are defined,
-and no space is taken up in `softfloat.o' by such functions. There is no
-provision for disabling the usual single- and double-precision formats.
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-softfloat/bits*/*/milieu.h
-
-The target-specific `milieu.h' header file provides declarations that are
-needed to compile SoftFloat. In addition, deviations from ISO/ANSI C by
-the compiler (such as names not properly declared in system header files)
-are corrected in this header if possible.
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-softfloat/bits*/*/softfloat-specialize
-
-This target-specific C source fragment defines:
-
--- whether tininess for underflow is detected before or after rounding by
- default;
--- what (if anything) special happens when exceptions are raised;
--- how signaling NaNs are distinguished from quiet NaNs;
--- the default generated quiet NaNs; and
--- how NaNs are propagated from function inputs to output.
-
-These details are not decided by the IEC/IEEE Standard. This fragment is
-included verbatim within `softfloat.c' when SoftFloat is compiled.
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-softfloat/bits*/softfloat-macros
-
-This target-independent C source fragment defines a number of arithmetic
-functions used as primitives within the `softfloat.c' source. Most of the
-functions defined here are intended to be inlined for efficiency. This
-fragment is included verbatim within `softfloat.c' when SoftFloat is
-compiled.
-
-Target-specific variations on this file are possible. See the section
-_Processor-Specific_Optimization_of_`softfloat.c'_Using_`softfloat-macros'_
-below.
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-softfloat/bits*/softfloat.c
-
-The target-independent `softfloat.c' source file contains the body of the
-SoftFloat implementation.
-
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
-
-The inclusion of the files above within each other (using `#include') can be
-shown graphically as follows:
-
- softfloat/bits*/softfloat.c
- softfloat/bits*/*/milieu.h
- processors/*.h
- softfloat/bits*/*/softfloat.h
- softfloat/bits*/*/softfloat-specialize
- softfloat/bits*/softfloat-macros
-
-Note in particular that `softfloat.c' does not include the `processors'
-header file directly. Rather, `softfloat.c' includes the target-specific
-`milieu.h' header file, which in turn includes the processor header file.
-
-
--------------------------------------------------------------------------------
-Steps to Creating a `softfloat.o'
-
-Porting and/or compiling SoftFloat involves the following steps:
-
-1. If one does not already exist, create an appropriate `.h' file in the
- `processors' directory.
-
-2. If `BITS64' is defined in the `processors' header file, choose whether
- to compile the 32-bit or 64-bit implementation of SoftFloat. If
- `BITS64' is not defined, your only choice is the 32-bit implementation.
- The remaining steps occur within either the `bits32' or `bits64'
- subdirectories.
-
-3. If one does not already exist, create an appropriate target-specific
- subdirectory by copying the given `templates' directory.
-
-4. In the target-specific subdirectory, edit the files `softfloat-specialize'
- and `softfloat.h' to define the desired exception handling functions
- and mode control values. In the `softfloat.h' header file, ensure also
- that all declarations give the proper target-specific type (such as
- `int' or `long') corresponding to the target-independent type used in
- `softfloat.c' (such as `int32'). None of the type names declared in the
- `processors' header file should appear in `softfloat.h'.
-
-5. In the target-specific subdirectory, edit the files `milieu.h' and
- `Makefile' to reflect the current environment.
-
-6. In the target-specific subdirectory, execute `make'.
-
-For the targets that are supplied, if the expected compiler is available
-(usually `gcc'), it should only be necessary to execute `make' in the
-target-specific subdirectory.
-
-
--------------------------------------------------------------------------------
-Making `softfloat.o' a Library
-
-SoftFloat is not made into a software library by the supplied makefile.
-If desired, `softfloat.o' can easily be put into its own library (in Unix,
-`softfloat.a') using the usual system tool (in Unix, `ar').
-
-
--------------------------------------------------------------------------------
-Testing SoftFloat
-
-SoftFloat can be tested using the `testsoftfloat' program by the same
-author. The `testsoftfloat' program is part of the TestFloat package
-available at the Web page `http://HTTP.CS.Berkeley.EDU/~jhauser/arithmetic/
-TestFloat.html'.
-
-
--------------------------------------------------------------------------------
-Timing SoftFloat
-
-A program called `timesoftfloat' for timing the SoftFloat functions is
-included with the SoftFloat source code. Compiling `timesoftfloat' should
-pose no difficulties once `softfloat.o' exists. The supplied makefile
-will create a `timesoftfloat' executable by default after generating
-`softfloat.o'. See `timesoftfloat.txt' for documentation about using
-`timesoftfloat'.
-
-
--------------------------------------------------------------------------------
-Compiler Options and Efficiency
-
-In order to get good speed with SoftFloat, it is important that the compiler
-inline the routines that have been marked `INLINE' in the code. Even if
-inlining cannot be forced by an appropriate definition of the `INLINE'
-macro, the compiler may still be able to perform inlining on its own as
-an optimization. In that case, the makefile should be edited to give the
-compiler whatever option is required to cause it to inline small functions.
-
-The ability of the processor to do fast shifts has been assumed. Efficiency
-will not be as good on processors for which this is not the case (such as
-the original Motorola 68000 or Intel 8086 processors).
-
-
--------------------------------------------------------------------------------
-Processor-Specific Optimization of `softfloat.c' Using `softfloat-macros'
-
-The `softfloat-macros' source fragment defines arithmetic functions used
-as primitives by `softfloat.c'. This file has been written in a target-
-independent form. For a given target, it may be possible to improve on
-these functions using target-specific and/or non-ISO-C features (such
-as `asm' statements). For example, one of the ``macro'' functions takes
-two word-size integers and returns their full product in two words.
-This operation can be done directly in hardware on many processors; but
-because it is not available through standard C, the function defined in
-`softfloat-macros' uses four multiplies to achieve the same result.
-
-To address these shortcomings, a customized version of `softfloat-macros'
-can be created in any of the target-specific subdirectories. A simple
-modification to the target's makefile should be sufficient to ensure that
-the custom version is used instead of the generic one.
-
-
--------------------------------------------------------------------------------
-Contact Information
-
-At the time of this writing, the most up-to-date information about
-SoftFloat and the latest release can be found at the Web page `http://
-HTTP.CS.Berkeley.EDU/~jhauser/arithmetic/SoftFloat.html'.
-
-
|