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Diff for /gforth/doc/gforth.ds between versions 1.56 and 1.57

version 1.56, 2000/06/29 18:39:27 version 1.57, 2000/07/13 19:41:07
Line 8680  control structures}), with @code{if,}, @ Line 8680  control structures}), with @code{if,}, @
 @code{cs-pick}, @code{else,}, @code{while,}, and @code{repeat,}.  The  @code{cs-pick}, @code{else,}, @code{while,}, and @code{repeat,}.  The
 conditions are specified in a way specific to each assembler.  conditions are specified in a way specific to each assembler.
   
   Note that the register assignments of the Gforth engine can change
   between Gforth versions, or even between different compilations of the
   same Gforth version (e.g., if you use a different GCC version).  So if
   you want to refer to Gforth's registers (e.g., the stack pointer or
   TOS), I recommend defining your own words for refering to these
   registers, and using them later on; then you can easily adapt to a
   changed register assignment.  The stability of the register assignment
   is usually better if you build Gforth with @code{--enable-force-reg}.
   
   In particular, the resturn stack pointer and the instruction pointer are
   in memory in @code{gforth}, and usually in registers in
   @code{gforth-fast}.  The most common use of these registers is to
   dispatch to the next word (the @code{next} routine).  A portable way to
   do this is to jump to @code{' noop >code-address} (of course, this is
   less efficient than integrating the @code{next} code and scheduling it
   well).
   
 @node  Common Disassembler, 386 Assembler, Common Assembler, Assembler and Code Words  @node  Common Disassembler, 386 Assembler, Common Assembler, Assembler and Code Words
 @subsection Common Disassembler  @subsection Common Disassembler
   
Line 8706  to ensure that the end is recognized. Line 8723  to ensure that the end is recognized.
 The 386 assembler and disassembler included in Gforth was written by  The 386 assembler and disassembler included in Gforth was written by
 Andrew McKewan; it is in the public domain.  Andrew McKewan; it is in the public domain.
   
   The disassembler displays code in prefix Intel syntax.
   
   The assembler uses an Intel-inspired postfix syntax with reversed
   parameters.  As usual, a @code{,} is appended to the instruction names
   (including @code{rep,} etc.).
   
   The assembler is somewhat meager, missing a number of instructions
   (including FP) and absolute memory addressing modes.
   
   The registers have their usual names @code{eax} etc.  Immediate values
   are indicated by postfixing them with @code{#}, e.g., @code{3 #}.  Here
   are some examples of addressing modes:
   
   @example
   3 #
   eax
   100 [edi]
   4 [ebx] [ecx]
   0 [edi] [eax] *4 \ base register required!
   @end example
   
   Some example of instructions are:
   
   @example
   EAX EBX MOV,             \ move ebx,eax
   3 # EAX MOV,             \ mov eax,3
   100 [EDI] EAX MOV,       \ mov eax,100[edi]
   4 [EBX] [ECX] EAX MOV,   \ mov eax,4[ebx][ecx]
   16: EAX EBX MOV,         \ mov bx,ax
   @end example
   
   You cannot use the prefix @code{16:} with immediate operands.  The
   following forms are supported for binary instructions:
   
   @example
   <reg> <reg> <inst>
   <n> # <reg> <inst>
   <mem> <reg> <inst>
   <reg> <mem> <inst>
   @end example
   
   Immediate to memory is not supported.  The shift/rotate syntax is:
   
   @example
   <reg/mem> shl,
   <reg/mem> 4 shl,
   <reg/mem> cl shl,
   @end example
   
   Precede string instructions (@code{movs,} etc.) with @code{byte} to get
   the byte version.
   
   The control structure words @code{if,} @code{until,} etc. must be
   preceded by one of these conditions: @code{0= 0< u< u> < > ov ecx0<>}.
   You can invert the condition with @code{not} (Note that most of these
   words shadow some Forth words when @code{assembler} is before
   @code{forth} in the search path, e.g., in code words).  Currently the
   control structure words use one stack item, so you have to use
   @code{roll} instead of @code{cs-roll} to shuffle them (you can also use
   @code{swap} etc.).
   
 @node Alpha Assembler, MIPS assembler, 386 Assembler, Assembler and Code Words  @node Alpha Assembler, MIPS assembler, 386 Assembler, Assembler and Code Words
 @subsection Alpha Assembler  @subsection Alpha Assembler
   
Removed from v.1.56  
changed lines
  Added in v.1.57

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