Study Sheet - Chapter 7
Disclaimer: This study sheet covers important terms and concepts that I
found in the text. The absence of a specific item in the text from this list
does not mean that you are not responsible for knowing it. Blah,
blah, blah.
Assembly coding and assemblers (Sections 7.1-7.3)
QOD on page 509... "assembly code programming... is not for wimps and
weaklings"
Terms:
| assembler |
compiler |
translator |
| source language |
target language |
pure assembly language |
| pseudo-instructions/assembler
directives |
|
| macro definition |
macro call |
macro expansion |
| forward reference problem |
2-pass assembler |
| Instruction Location Counter (ILC) |
|
| symbol table |
binary search |
hash table |
You should understand:
- Common format on an assembly language statement
-
Difference between instructions and pseudo-instructions
-
Plusses and minuses of writing assembly code
-
Macros are different than functions, they are:
- Expanded during assembly, not execution
- Placed in-line, not called like functions
- Don't have return values
- The two passes of an assembler:
- What each pass does
- The forward reference problem
- The symbol table
Linking and loading (Section 7.4)
Terms:
| linker |
loader |
object module |
executable |
| relocation problem |
external reference problem |
relocation constant |
entry points |
| external symbols |
binding time |
position independent |
dynamic linking |
| Dynamic Link Library (DLL) |
implicit linking |
import library |
explicit linking |
| shared library |
host library |
target library |
|
Key points:
- Understand the process of creating an executable: source
files, translators, object files and libraries, linker (as in Fig 7-13 on
page 531)
- The basic problems solved by the linker:
- relocation problem - setting the starting address of a
module and adjusting all references by a relocation constant
- external reference problem - finding the address of external
functions and variables
- all the goodies in the example shown in section 7.4
- Six parts of an object module:
- Identification - name of the module other accounting
information
- Entry point table - public objects (like .globl in our assembly
code)
- External reference table - symbols that are defined outside
this module (.extrn)
- Machine instructions and constants - the code
- Relocation dictionary - list of addresses in part 4 that need
to be relocated
- End of module- checksum, parity check
- Six possibilities for binding time, when program is 1) written, 2)
translated, 3) linked, 4) loaded, 5) base register is loaded, 6) executed
- Dynamic linking using DLL's
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