Download MPLAB IDE Simulator, Editor User's Guide

Shell
The MPASM assembler shell is a prompted input interface to the macro
assembler. There are two MPASM assembler shells: one for the DOS version
and one for the Windows version.
Simulator
A software program that models the operation of the PICmicro
microprocessor.
Single Step
This command steps though code, one instruction at a time. After each
instruction, MPLAB IDE updates register windows, watch variables, and
status displays so you can analyze and debug instruction execution.
You can also single step C compiler source code, but instead of executing
single instructions, MPLAB IDE will execute all assembly level instructions
generated by the line of the high level C statement.
Skew
The information associated with the execution of an instruction appears on
the processor bus at different times. For example, the executed opcode
appears on the bus as a fetch during the execution of the previous instruction,
the source data address and value and the destination data address appear
when the opcode is actually executed, and the destination data value appears
when the next instruction is executed. The trace buffer captures the
information that is on the bus at one instance. Therefore, one trace buffer
entry will contain execution information for three instructions. The number of
captured cycles from one piece of information to another for a single
instruction execution is referred to as the skew.
Skid
When a hardware break point is used to halt the processor, one or more
additional instructions may be executed before the processor halts. The
number of extra instructions executed after the intended break point is
referred to as the skid.
Source Code – Assembly
Source code consists of PICmicro MCU instructions and MPASM assembler
directives and macros that will be translated into machine code by an
assembler.
Source Code – C
A program written in the high level language called “C” which will be
converted into PICmicro MCU machine code by a compiler. Machine code is
suitable for use by a PICmicro MCU or Microchip development system
product like MPLAB IDE.
 2001 Microchip Technology Inc.
DS51025E-page 253