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Assembly Language Terms
COE538 Assembly Basics Cheat Sheet
Instruction Abbreviations
- LDAA → LoaD Accumulator A
- Example:
LDAA #55→ Load A with 55
- Example:
- LDAB → LoaD Accumulator B
- ADDA → ADd to Accumulator A
- Example:
ADDA $20→ A = A + value at memory address $20
- Example:
- SUBA → SUBtract from Accumulator A
- STAA → STore Accumulator A into memory
- TFR → TRansFeR between registers
- EXG → EXchanGe registers
- INCA → INCrement A → A = A + 1
- NOP → No OPeration (do nothing)
Special Symbols
-
#→ Immediate Value- Means: “Use this number directly, not from memory.”
- Example:
LDAA #55→ A = 55
-
$→ Hexadecimal Number- Means: “The following number is in hexadecimal.”
- Example:
LDAA $20→ A = value stored at memory[0x20]
-
@→ Indirect Addressing (pointer)- Means: “Use the memory location stored in a register or memory cell.”
- Example:
LDAA @X→ A = memory[X]
C Language Analogy
LDAA #55→A = 55;LDAA $20→A = memory[0x20];LDAA @X→A = memory[X];
CCR (Condition Code Register) Flags
- C (Carry): Unsigned overflow → e.g. 255 + 1 = 0 with C = 1
- V (Overflow): Signed overflow → e.g. 127 + 1 = -128 with V = 1
- Z (Zero): Result is zero
- N (Negative): Result is negative (most significant bit = 1)
Assembly Language Terms
https://mizuki.mysqil.com/posts/assembly/ Some information may be outdated
