Lecture-2 - Department of Computer Science
... method known as two's complement. A little more
complicated than sign-and-magnitude but not that
much and it has only one zero value.
To have –9 in two's complement, you invert all the
bits in the representation of 9 and add 1.
You can achieve the same result by starting from
the right; find the fir ...
Chapter 2 Parts of a Computer System
... ESP addresses an area of memory called stack.
The stack (堆栈) memory is accessed using a
LIFO (last-in, first-out 后进先出) method.
ESP points to the top of the stack, but will be
modified with a push or pop instruction.
This register is SP (16 bits) in the real mode
and ESP (32 bits) in the protected mo ...
Instruction level architecture
... • Pentiums have a 32 bit word but fetch
things 64 bits at a time
– They run faster if you waste a few bytes and
align operands on addresses divisible by 8
– What you especially want to avoid is a single
reference that spans two double words
Copyright © 2005 - Curt Hill
... • The address of the data an instruction operates on is called the effective address of that
• Each instruction has information which tells the HCS12 the address of the data in
memory it operates on.
• The addressing mode of the instruction tells the HCS12 how to figure out the effectiv ...
Some “facts” about software…
... • How does the data get in there?
– Mask programming – data is programmed in at the
time of silicon fabrication
– PROM – special programming devices allow the
user to write data one time
– EPROM – data is erased under ultra-violet light or
electronically, but must be entirely erased and
rewritten (c ...
Mnemonic operation codes
... instructions eliminates the need to memorize numeric
operation codes. It also enables the assembler to provide
helpful diagnostics, for example indication of misspelt
Bringing Bits, Bytes, Devices and Computers to Life
... Store the PC at address X and jump to X=1
Load contents of address X into AC.
Store the contents of AC at address X.
Add the contents of address X to AC.
Subtract the contents of Address X from AC.
Input a value from the keyboard into AC.
Output the value in AC to the display.
This article is about the ARGUS language and machine language of the Honeywell 800 and 1800 computers. The name ARGUS was an acronym, standing for: Automatic Routine Generating and Updating System.ARGUS was an Assembly Language devised in the 1960s by Honeywell for their Honeywell 800 and 1800 computers. As with other Assembly Languages, each line of ARGUS was copied on to one card and related to one word in memory, except that one ARGUS command, RESERVE, could reserve any specified number of words in the position specified. The RESERVE command was also exceptional in not prescribing the initial data in the reserved words. With a few exceptions Machine Language words were coded in the same order as the ARGUS lines.