(Address transfer operators): mixed bug in

DECX's MOD value.

1 files changed, 39 insertions, 39 deletions

diff --git a/doc/mdk_tut.texi b/doc/mdk_tut.texi
index c2b3ab1..42111fc 100644
--- a/doc/mdk_tut.texi
+++ b/doc/mdk_tut.texi
@@ -1,10 +1,10 @@
 @c -*-texinfo-*-
 @c This is part of the GNU MDK Reference Manual.
-@c Copyright (C) 2000, 2001, 2002
+@c Copyright (C) 2000, 2001, 2002, 2003
 @c   Free Software Foundation, Inc.
 @c See the file mdk.texi for copying conditions.
 
-@c $Id: mdk_tut.texi,v 1.7 2002/04/08 00:26:37 jao Exp $
+@c $Id: mdk_tut.texi,v 1.8 2003/06/02 23:19:52 jao Exp $
 
 @node MIX and MIXAL tutorial, Getting started, Installing MDK, Top
 @comment  node-name,  next,  previous,  up
@@ -23,7 +23,7 @@ on these topics, which will teach you the basics of the MIX architecture
 and how to program a MIX computer using MIXAL.
 
 @menu
-* The MIX computer::            Architecture and instruction set 
+* The MIX computer::            Architecture and instruction set
                                 of the MIX computer.
 * MIXAL::                       The MIX assembly language.
 @end menu
@@ -36,8 +36,8 @@ In this section, you will find a description of the MIX computer,
 its components and instruction set.
 
 @menu
-* MIX architecture::            
-* MIX instruction set::         
+* MIX architecture::
+* MIX instruction set::
 @end menu
 
 @node MIX architecture, MIX instruction set, The MIX computer, The MIX computer
@@ -75,7 +75,7 @@ significant one. The sign is denoted by index 0. Graphically,
  -----------------------------------------------
 |   0   |   1   |   2   |   3   |   4   |   5   |
  -----------------------------------------------
-|  +/-  | byte  | byte  | byte  | byte  | byte  |     
+|  +/-  | byte  | byte  | byte  | byte  | byte  |
  -----------------------------------------------
 @end example
 @noindent
@@ -142,7 +142,7 @@ Input-output block devices. Each device is labelled as @code{un}, where
 @code{n} runs from 0 to 20. In Knuth's definition, @code{u0} through
 @code{u7} are magnetic tape units, @code{u8} through @code{15} are disks
 and drums, @code{u16} is a card reader, @code{u17} is a card writer,
-@code{u18} is 
+@code{u18} is
 a line printer and, @code{u19} is a typewriter terminal, and @code{u20},
 a paper tape. Our implementation maps these devices to disk files,
 except for @code{u19}, which represents the standard output.
@@ -165,7 +165,7 @@ following table:
 @item  16 @tab O @tab 17 @tab P @tab 18 @tab Q @tab 19 @tab R
 @item  20 @tab s @tab 21 @tab p @tab 22 @tab S @tab 23 @tab T
 @item  24 @tab U @tab 25 @tab V @tab 26 @tab W @tab 27 @tab X
-@item  28 @tab Y @tab 29 @tab Z @tab 30 @tab 0 @tab 31 @tab 1 
+@item  28 @tab Y @tab 29 @tab Z @tab 30 @tab 0 @tab 31 @tab 1
 @item  32 @tab 2 @tab 33 @tab 3 @tab 34 @tab 4 @tab 35 @tab 5
 @item  36 @tab 6 @tab 37 @tab 7 @tab 38 @tab 8 @tab 39 @tab 9
 @item  40 @tab . @tab 41 @tab , @tab 42 @tab ( @tab 43 @tab )
@@ -204,18 +204,18 @@ remaininig subsections are devoted to describing the actual instructions
 available to the MIX programmer.
 
 @menu
-* Instruction structure::       
-* Loading operators::           
-* Storing operators::           
-* Arithmetic operators::        
-* Address transfer operators::  
-* Comparison operators::        
-* Jump operators::              
-* Input-output operators::      
-* Conversion operators::        
-* Shift operators::             
-* Miscellaneous operators::     
-* Execution times::             
+* Instruction structure::
+* Loading operators::
+* Storing operators::
+* Arithmetic operators::
+* Address transfer operators::
+* Comparison operators::
+* Jump operators::
+* Input-output operators::
+* Conversion operators::
+* Shift operators::
+* Miscellaneous operators::
+* Execution times::
 @end menu
 
 @node Instruction structure, Loading operators, MIX instruction set, MIX instruction set
@@ -251,12 +251,12 @@ or, graphically,
  ------------------------------------------------
 |   0   |   1   |   2   |   3   |   4   |   5    |
  ------------------------------------------------
-|        ADDRESS        | INDEX |  MOD  | OPCODE |     
+|        ADDRESS        | INDEX |  MOD  | OPCODE |
  ------------------------------------------------
 @end example
 
 For a given instruction, @samp{M} stands for
-the memory address obtained after indexing the ADDRESS subfield 
+the memory address obtained after indexing the ADDRESS subfield
 (using its INDEX byte), and @samp{V} is the contents of the
 subfield indicated by MOD of the memory cell with address @samp{M}. For
 instance, suppose that we have the following contents of MIX registers
@@ -286,10 +286,10 @@ V = [M](MOD) = (- 10 11 00 11 22)(1:3) = + 00 00 10 11 00
 
 Note that, when computing @samp{V} using a word and an fspec, we apply
 a left padding to the bytes selected by @samp{MOD} to obtain a
-complete word as the result. 
+complete word as the result.
 
 In the following subsections, we will
-assing to each MIX instruction a mnemonic, or symbolic name. For
+assign to each MIX instruction a mnemonic, or symbolic name. For
 instance, the mnemonic of @samp{OPCODE} 10 is @samp{LD2}. Thus we can
 rewrite the above instruction as
 
@@ -446,7 +446,7 @@ rX register and memory contents.
 
 @ftable @code
 @item ADD
-Add and set OV if overflow. OPCODE = 1, MOD = fspec. 
+Add and set OV if overflow. OPCODE = 1, MOD = fspec.
 @w{@code{rA <- rA +V}}.
 @item SUB
 Sub and set OV if overflow. OPCODE = 2, MOD = fspec.
@@ -506,7 +506,7 @@ Increase [rIi] by @samp{M}. OPCODE = 48 + i, MOD = 0. @code{rIi <- rIi + M}.
 @item DECA
 Decrease [rA] by @samp{M}. OPCODE = 48, MOD = 1. @code{rA <- rA - M}.
 @item DECX
-Decrease [rX] by @samp{M}. OPCODE = 55, MOD = 0. @code{rX <- rX - M}.
+Decrease [rX] by @samp{M}. OPCODE = 55, MOD = 1. @code{rX <- rX - M}.
 @item DECi
 Decrease [rIi] by @samp{M}. OPCODE = 48 + i, MaOD = 0. @code{rIi <- rIi - M}.
 @end ftable
@@ -628,7 +628,7 @@ using the following instructions:
 @itemx JANZ
 @itemx JANP
 Jump if the content of rA is, respectively, negative, zero, positive,
-non-negative, non-zero or non-positive. 
+non-negative, non-zero or non-positive.
 OPCODE = 40, MOD = 0, 1, 2, 3, 4, 5.
 @item JXN
 @itemx JXZ
@@ -637,7 +637,7 @@ OPCODE = 40, MOD = 0, 1, 2, 3, 4, 5.
 @itemx JXNZ
 @itemx JXNP
 Jump if the content of rX is, respectively, negative, zero, positive,
-non-negative, non-zero or non-positive. 
+non-negative, non-zero or non-positive.
 OPCODE = 47, MOD = 0, 1, 2, 3, 4, 5.
 @item JiN
 @itemx JiZ
@@ -646,7 +646,7 @@ OPCODE = 47, MOD = 0, 1, 2, 3, 4, 5.
 @itemx JiNZ
 @itemx JiNP
 Jump if the content of rIi is, respectively, negative, zero, positive,
-non-negative, non-zero or non-positive. 
+non-negative, non-zero or non-positive.
 OPCODE = 40 + i, MOD = 0, 1, 2, 3, 4, 5.
 @end ftable
 
@@ -817,13 +817,13 @@ arbitrary units) of the MIX instructions are given.
 @item @code{DIV} @tab 12 @tab @code{NUM} @tab 10 @tab @code{CHAR}
 @tab 10 @tab @code{HLT} @tab 10
 @item @code{SLx} @tab 2 @tab @code{SRx} @tab 2 @tab @code{LDx}
-@tab  2 @tab @code{STx} @tab 2 
+@tab  2 @tab @code{STx} @tab 2
 @item @code{JBUS} @tab 1 @tab @code{IOC} @tab 1 @tab @code{IN}
 @tab  1@tab @code{OUT} @tab 1
 @item @code{JRED} @tab 1 @tab @code{Jx} @tab 1 @tab @code{INCx}
-@tab  1 @tab @code{DECx} @tab 1 
+@tab  1 @tab @code{DECx} @tab 1
 @item @code{ENTx} @tab 1 @tab @code{ENNx} @tab 1 @tab @code{CMPx}
-@tab  1 @tab @code{MOVE} @tab 1+2F  
+@tab  1 @tab @code{MOVE} @tab 1+2F
 @end multitable
 
 In the above table, 'F' stands for the number of blocks to be moved
@@ -911,7 +911,7 @@ assembly pseudoinstruction (e.g. @code{ORG}, @code{EQU}),
 is an expression evaluating to the address subfield of the instruction,
 @item INDEX
 is an expression evaluating to the index subfield of the instruction, which
-defaults to 0 (i.e., no use of indexing) and can only be used when 
+defaults to 0 (i.e., no use of indexing) and can only be used when
 @code{ADDRESS} is present,
 @item MOD
 is an expression evaluating to the mod subfield of the instruction. Its
@@ -993,7 +993,7 @@ The assembler will generate two binary instructions (@code{NOP} (@w{+ 00
 addresses 2000 and 2001. Execution of the program will begin at address
 2000. Every MIXAL program should also include a @code{HLT} instruction,
 which will mark the end of program execution (but not of program
-compilation). 
+compilation).
 
 The @code{EQU} directive allows the definition of symbolic names for
 specific values. For instance, we could rewrite the above program as
@@ -1030,7 +1030,7 @@ the assembler encounters the following code snippet
 @end example
 @noindent
 it will assign to the memory cell number 1150 the contents @w{- 00 06 61
-11 49} (which corresponds to the decimal value -1823473). 
+11 49} (which corresponds to the decimal value -1823473).
 
 Finally, the @code{ALF} directive let's you specify the memory contents
 as a set of five (quoted) characters, which are translated by the
@@ -1109,7 +1109,7 @@ to the same, multiplied by 64 to the fifth power) divided by
 18-8*3 = 30
 14/3 = 4
 1+3:11 = 4:11 = 43
-1//64 = (01 00 00 00 00)/(00 00 00 01 00) = (01 00 00 00 00)
+1//64 = (01 00 00 00 00 00)/(00 00 00 01 00) = (01 00 00 00 00)
 @end example
 @noindent
 Note that all MIXAL expressions evaluate to a MIX word (by definition).
@@ -1120,7 +1120,7 @@ an unary operator) in the @code{ADDRESS} part of a MIXAL instruction,
 e.g.
 
 @example
-* OK: stand alone future reference 
+* OK: stand alone future reference
          STA  -S1(1:5)
 * ERROR: future reference in expression
          LDX  2-S1
@@ -1250,7 +1250,7 @@ thank Philip E. King for pointing these two special cases of local
 symbol usage to him.},
 
 @example
-		ORIG 1999 
+		ORIG 1999
 ST		NOP
 3H		CON 10
 		ENT1 *
@@ -1292,7 +1292,7 @@ equivalent to the following:
 L         EQU  5
           LDA  a
 @dots{}
-a         CON  20-L    
+a         CON  20-L
           END  start
 @end example