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--- lehrkraefte:blc:informatik:efi-2023:assembler [2024/04/02 15:35]
Ivo Blöchliger
+++ lehrkraefte:blc:informatik:efi-2023:assembler [2024/04/23 15:04] (current)
Ivo Blöchliger [Funktionsweise einer CPU]
@@ Line 94: / Line 94: @@
 <hidden Lösungsvorschlag>
-	MOV A,123
+<code asm>
-	MOV C, 232
+	MOV A, 237
-	CALL showNumber
+	MOV C,232
-        HLT
+	CALL showByte
+	HLT
-; Params in register:
+; Byte in A
-;   A number to print
+; Address in C
-;   C address to display digit
+showByte:
-showNumber:
+	PUSH A   ; Save registers
-    PUSH C
+	PUSH B
-    ADD C,2
+	PUSH C
-numberLoop:
+	ADD C,2
-    PUSH A
+loopA:
-    PUSH 10
+	PUSH A   ; SAVE A
-    CALL mod
+	PUSH 10  ; Push modulo op to stack
-    INC SP      ; Clean  up stack!
+	CALL mod
-    MOV B,A
+	INC SP   ; Correct Stackpointer
-    CALL showDigit
+	MOV B,A  ; digit to B
-    DEC C
+	CALL showDigit  ;
-    POP A
+	DEC C  ; Adjust for next address
-    DIV 10
+	POP A  ; restore A
-    JNZ numberLoop
+	DIV 10
-    POP C
+	JNZ loopA
-    RET
+	POP C
+	POP B
+	POP A
+	RET
+</code>
 </hidden>
 </WRAP>
@@ Line 206: / Line 211: @@
 Bonus: Implementieren Sie QuickSort.
+<hidden Animationen auf 7-Segment-Anzeige>
+<code asm>
+; Simple example
+; Writes Hello World to the output
+start:
+	MOV B, dataStart
+loop:
+	MOV A, 253
+	MOV C, [B]
+	MOV [A], C
+	MOV C, [B+1]
+	MOV [A+1], C
+	MOV C, [B+2]
+	MOV [A+2], C
+	ADD B, 3
+	CMP B, dataEnd
+	JNZ loop
+	JMP start
+dataStart:
+	DB 8
+	DB 8
+	DB 8
+	DB 0
+	DB 8
+	DB 12
+	DB 0
+	DB 0
+	DB 14
+	DB 0
+	DB 0
+	DB 7
+	DB 0
+	DB 1
+	DB 3
+	DB 1
+	DB 1
+	DB 1
+	DB 33
+	DB 1
+	DB 0
+	DB 49
+	DB 0
+	DB 0
+	DB 56
+	DB 0
+	DB 0
+	DB 24
+	DB 8
+	DB 0
+dataEnd:
+</code>
+</hidden>
+<hidden Animation mit Bytes in Strings codier (unnötig hackisch)>
+<code asm>
+start:
+	MOV B, dataStart
+loop:
+	MOV C, [B]
+	MOV A, [B+6]
+	MOV [253], C
+	MOV [254], A
+	MOV [255], C
+	INC B
+	CMP B, dataEnd
+	JNZ loop
+	JMP start
+dataStart:
+	DB "!0␌"
+dataEnd:
+	DB "!␌0"
+</code>
+</hidden>
+<hidden Quicksort-Implementation>
+<code asm>
+	JMP start
+arrayStart:
+        DB 4
+	DB 2
+	DB 7
+	DB 9
+	DB 8
+	DB 7
+	DB 4
+	DB 5
+	DB 8
+	DB 9
+	DB 4
+	DB 3
+	DB 6
+	DB 1
+start:
+	MOV A, arrayStart
+	MOV B, start
+	DEC B
+	call quicksort
+	HLT
+quicksort:
+;first elements address in A
+;last elements address in B
+	PUSH D
+	PUSH C
+	PUSH B
+	PUSH A
+	MOV C,B
+	SUB C,A
+	JBE ende    ; bail if B-A <= 0
+	MOV [a0], A   ; save bounds
+	MOV [b0], B
+	MOV C, [A]    ; Pivot value
+	INC A
+leftloop:  ; while C>=[A]: A++
+	CMP C,[A]
+	JC rightloop   ; break if C<[A]
+	INC A
+	CMP A,B
+	JBE leftloop   ; repeat if A<=B
+rightloop:   ; while C<=[B]; B--
+	CMP C,[B]
+	JA swapping   ; break if C>[B]
+	DEC B
+	CMP A,B
+	JB rightloop  ; repeat if A<B
+swapping:   ; Swaps [A] and [B], if A<B
+	CMP A,B
+	JAE setpivot
+	MOV D, [A]
+	PUSH D
+	MOV D, [B]
+	MOV [A], D
+	POP D
+	MOV [B], D
+	INC A
+	DEC B
+	JMP leftloop
+setpivot:
+	CMP A,[b0]
+	JBE ok
+	MOV A,[b0]
+	INC A
+ok:    ; swap pivot and [A]
+	DEC A
+	MOV [p0], A   ; index of pivot
+	MOV D,[A]
+	MOV [A], C
+	MOV C,[a0]
+	MOV [C], D
+;recursion
+	MOV A, [a0]
+	MOV B, [p0]
+	DEC B
+	PUSH [p0]   ; save p0 and b0
+	PUSH [b0]
+	call quicksort
+	POP B       ; restore p0 and b0
+	POP A
+	INC A
+	call quicksort
+ende:
+	POP A
+	POP B
+	POP C
+	POP C
+	RET
+a0:	DB 0
+b0:	DB 0
+p0:	DB 0
+</code>
+</hidden>
 </WRAP>
 ===== Hackme =====
@@ Line 277: / Line 485: @@
 </hidden>
 </hidden>
+===== Mögliche Prüfungsfragen =====
+Die Ausgabe auf die drei 7-Segment Anzeigen erfolgt auf die Adressen 253 bis 255.
+Die Bits auf der Anzeige sind wie folgt nummeriert:
+<code txt>
++--0--+
+     1
+:--6--:
+     2
++--3--+
+</code>