Explain how the LES and LDS instructions load segment and offset registers from memory according to Intel's byte significance (little-endian) ordering, detailing parameter syntax and subroutine application.
Ch 07: Video Memory & Screen Display
Covers direct text manipulation on 80x25 character screens, calculating screen offsets ((Row * 80 + Col) * 2), attribute byte structure (foreground, background, blink bit), and converting binary values to ASCII strings.
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CS401 - Computer Architecture and Assembly Language Programming Examination Practice
Timed practice exam simulation for CS401 - Computer Architecture and Assembly Language Programming.
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Describe the implementation of text mode screen scrolling using the REP MOVSW instruction in 8088 assembly language, specifying source/destination memory offset setup, row count calculations, and clearing the bottom row.
Write a complete 8088 assembly subroutine using REPE CMPSB to compare two null-terminated strings for equality, and explain why debuggers show the prefix byte for REP and REPE identically.
During the execution of the STOSW (Store String Word) instruction when the Direction Flag (DF) is clear (0), how is the destination index register updated?
During the execution of the STOSB (Store String Byte) instruction when the Direction Flag (DF) is clear (0), how is the destination index register (DI) updated?
When the REP prefix is executed alongside the STOSW instruction, how is the count register (CX) updated in each iteration?
By how many bytes is the index register modified during a single execution of the STOSB (Store String Byte) instruction?
Which assembly language instruction is used to clear the Direction Flag (DF = 0) to enable autoincrement mode for string operations?
During the execution of the STOSW instruction when the Direction Flag (DF) is clear (0), how is the Destination Index (DI) register updated?
In 8088 assembly language, which specialized family of instructions allows direct memory-to-memory block data transfers without loading intermediate general-purpose registers?