Diff for /gforth/Attic/gforth.ds between versions 1.24 and 1.25

version 1.24, 1995/11/15 17:29:07 version 1.25, 1995/11/28 18:45:28
Line 44  Copyright @copyright{} 1995 Free Softwar Line 44  Copyright @copyright{} 1995 Free Softwar
 @center for version 0.1  @center for version 0.1
 @sp 2  @sp 2
 @center Anton Ertl  @center Anton Ertl
   @center Bernd Paysan
 @sp 3  @sp 3
 @center This manual is under construction  @center This manual is under construction
   
Line 2088  machine code), and for defining the the Line 2089  machine code), and for defining the the
 nature of Gforth poses a few problems: First of all. Gforth runs on  nature of Gforth poses a few problems: First of all. Gforth runs on
 several architectures, so it can provide no standard assembler. What's  several architectures, so it can provide no standard assembler. What's
 worse is that the register allocation not only depends on the processor,  worse is that the register allocation not only depends on the processor,
 but also on the gcc version and options used.  but also on the @code{gcc} version and options used.
   
 The words Gforth offers encapsulate some system dependences (e.g., the  The words that Gforth offers encapsulate some system dependences (e.g., the
 header structure), so a system-independent assembler may be used in  header structure), so a system-independent assembler may be used in
 Gforth. If you do not have an assembler, you can compile machine code  Gforth. If you do not have an assembler, you can compile machine code
 directly with @code{,} and @code{c,}.  directly with @code{,} and @code{c,}.
Line 2108  These words are rarely used. Therefore t Line 2109  These words are rarely used. Therefore t
 which is usually not loaded (except @code{flush-icache}, which is always  which is usually not loaded (except @code{flush-icache}, which is always
 present). You can load them with @code{require code.fs}.  present). You can load them with @code{require code.fs}.
   
   In the assembly code you will want to refer to the inner interpreter's
   registers (e.g., the data stack pointer) and you may want to use other
   registers for temporary storage. Unfortunately, the register allocation
   is installation-dependent.
   
   The easiest solution is to use explicit register declarations
   (@pxref{Explicit Reg Vars, , Variables in Specified Registers, gcc.info,
   GNU C Manual}) for all of the inner interpreter's registers: You have to
   compile Gforth with @code{-DFORCE_REG} (configure option
   @code{--enable-force-reg}) and the appropriate declarations must be
   present in the @code{machine.h} file (see @code{mips.h} for an example;
   you can find a full list of all declarable register symbols with
   @code{grep register engine.c}). If you give explicit registers to all
   variables that are declared at the beginning of @code{engine()}, you
   should be able to use the other caller-saved registers for temporary
   storage. Alternatively, you can use the @code{gcc} option
   @code{-ffixed-REG} (@pxref{Code Gen Options, , Options for Code
   Generation Conventions, gcc.info, GNU C Manual}) to reserve a register
   (however, this restriction on register allocation may slow Gforth
   significantly).
   
   If this solution is not viable (e.g., because @code{gcc} does not allow
   you to explicitly declare all the registers you need), you have to find
   out by looking at the code where the inner interpreter's registers
   reside and which registers can be used for temporary storage. You can
   get an assembly listing of the engine's code with @code{make engine.s}.
   
   In any case, it is good practice to abstract your assembly code from the
   actual register allocation. E.g., if the data stack pointer resides in
   register @code{$17}, create an alias for this register called @code{sp},
   and use that in your assembly code.
   
 Another option for implementing normal and defining words efficiently  Another option for implementing normal and defining words efficiently
 is: adding the wanted functionality to the source of Gforth. For normal  is: adding the wanted functionality to the source of Gforth. For normal
 words you just have to edit @file{primitives}, defining words (for fast  words you just have to edit @file{primitives}, defining words (for fast
 defined words) probably require changes in @file{engine.c},  defined words) may require changes in @file{engine.c},
 @file{kernal.fs}, @file{prims2x.fs}, and possibly @file{cross.fs}.  @file{kernal.fs}, @file{prims2x.fs}, and possibly @file{cross.fs}.
   
   
Line 2384  characters is determined by the locale y Line 2417  characters is determined by the locale y
   
 @item division rounding:  @item division rounding:
 installation dependent. @code{s" floored" environment? drop .}. We leave  installation dependent. @code{s" floored" environment? drop .}. We leave
 the choice to gcc (what to use for @code{/}) and to you (whether to use  the choice to @code{gcc} (what to use for @code{/}) and to you (whether to use
 @code{fm/mod}, @code{sm/rem} or simply @code{/}).  @code{fm/mod}, @code{sm/rem} or simply @code{/}).
   
 @item values of @code{STATE} when true:  @item values of @code{STATE} when true:
Line 3701  VolksForth descends from F83. It was wri Line 3734  VolksForth descends from F83. It was wri
 Pennemann, Georg Rehfeld and Dietrich Weineck for the C64 (called  Pennemann, Georg Rehfeld and Dietrich Weineck for the C64 (called
 UltraForth there) in the mid-80s and ported to the Atari ST in 1986.  UltraForth there) in the mid-80s and ported to the Atari ST in 1986.
   
 Laxen and Perry wrote F83 as a model implementation of the  Hennry Laxen and Mike Perry wrote F83 as a model implementation of the
 Forth-83 standard. !! Pedigree? When?  Forth-83 standard. !! Pedigree? When?
   
 A team led by Bill Ragsdale implemented fig-Forth on many processors in  A team led by Bill Ragsdale implemented fig-Forth on many processors in

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  Added in v.1.25


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