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Diffstat (limited to 'doc/mdk_tut.texi')
| -rw-r--r-- | doc/mdk_tut.texi | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/doc/mdk_tut.texi b/doc/mdk_tut.texi index 821e52f..e2d3a15 100644 --- a/doc/mdk_tut.texi +++ b/doc/mdk_tut.texi @@ -182,7 +182,7 @@ above components, and which is able to execute a rich set of instructions (constituting its machine language, similar to those commonly found in real CPUs), including arithmetic, logical, storing, comparison and jump instructions. Being a typical von Neumann computer, -the MIX CPU fetchs binary instructions from memory sequentially (unless +the MIX CPU fetches binary instructions from memory sequentially (unless a jump instruction is found), and stores the address of the next instruction to be executed in an internal register called @dfn{location counter} (also known as program counter in other architectures). @@ -198,7 +198,7 @@ of the available MIX binary instructions. The following subsections fully describe the instruction set of the MIX computer. We begin with a description of the structure of binary instructions and the notation used to refer to their subfields. The -remaininig subsections are devoted to describing the actual instructions +remaining subsections are devoted to describing the actual instructions available to the MIX programmer. @menu @@ -466,7 +466,7 @@ of the register @samp{A}, so that we are able to handle 10-byte numbers whose more significant bytes are those of @samp{rA} (the sign of this 10-byte number is that of @samp{rA}: @samp{rX}'s sign is ignored). -Addition and substraction of MIX words can give rise to overflows, since +Addition and subtraction of MIX words can give rise to overflows, since the result is stored in a register with room to only 5 bytes (plus sign). When this occurs, the operation result modulo @w{1,073,741,823} (the maximum value storable in a MIX word) is stored in @samp{rA}, and @@ -521,7 +521,7 @@ can use the binary instruction @w{+ 31 16 00 03 48}, or, symbolically, ENNA 2000 @end example @noindent -Used in conjuction with the store operations (@samp{STA}, @samp{STX}, +Used in conjunction with the store operations (@samp{STA}, @samp{STX}, etc.), these instructions also allow you to set memory cells contents to concrete values. @@ -672,7 +672,7 @@ Transfer a block of words from memory (starting at address M) to the specified unit. OPCODE = 37, MOD = I/O unit. @item IOC -Perfom a control operation (given by M) on the specified unit. +Perform a control operation (given by M) on the specified unit. OPCODE = 35, MOD = I/O unit. @item JRED Jump to M if the specified unit is ready. @@ -827,9 +827,9 @@ counter, while @samp{HLT} usually marks program termination. @cindex time When writing MIXAL programs (or any kind of programs, for that -matter), whe shall often be interested in their execution -time. Loosely speaking, we will interested in the answer to the -question: how long takes a program to execute? Of course, this +matter), we shall often be interested in their execution +time. Loosely speaking, we will be interested in the answer to the +question: how long does it take a program to execute? Of course, this execution time will be a function of the input size, and the answer to our question is commonly given as the asymptotic behaviour as a function of the input size. At any rate, to compute this asymptotic @@ -950,7 +950,7 @@ defaults to 0 (i.e., no use of indexing) and can only be used when is an expression evaluating to the mod subfield of the instruction. Its default value, when omitted, depends on @code{OPCODE}, @item COMMENT -any number of spaces after the operand mark the beggining of a comment, +any number of spaces after the operand mark the beginning of a comment, i.e. any text separated by white space from the operand is ignored by the assembler (note that spaces are not allowed within the @samp{OPERAND} field). @@ -964,8 +964,8 @@ column number at which each of these instruction parts must start. The MIXAL assembler included in @sc{mdk}, @code{mixasm}, does not impose such restriction.}. -We have already listed the mnemonics associated will each MIX -instructions; sample MIXAL instructions representing MIX instructions +We have already listed the mnemonics associated with each MIX +instruction; sample MIXAL instructions representing MIX instructions are: @example HERE LDA 2000 HERE represents the current location counter @@ -1014,8 +1014,8 @@ directive to mark the initial value of the assembler's location counter instruction). Thus, a minimal MIXAL program would be @example - ORIG 2000 set the initial compilation adress - NOP this instruction will be loaded at adress 2000 + ORIG 2000 set the initial compilation address + NOP this instruction will be loaded at address 2000 HLT and this one at address 2001 END 2000 end of program; start at address 2000 this line is not parsed by the assembler @@ -1065,7 +1065,7 @@ the assembler encounters the following code snippet it will assign to the memory cell number 1150 the contents @w{- 00 06 61 11 49} (which corresponds to the decimal value -1823473). -Finally, the @code{ALF} directive let's you specify the memory contents +Finally, the @code{ALF} directive lets you specify the memory contents as a set of five (optionally quoted) characters, which are translated by the assembler to their byte values, conforming in that way the binary word that is to be stored in the corresponding memory cell. This |