C128-ASSEMBLER-ASL-LSR-DUO 
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TOOL: 		Built-in ML-Monitor {Commodore C128}
Language: 	Machine Language {Assembler}
Extra:		none
Author: 	Misel Zivanovic
Note:		(C) 22th of OCTOBER 2026 - www.lived.ch, mzretro.ch
Doc Revision:	1.0
Last update:	14:32 22.10.2026
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BOTH EXAMPLES BELOW CAN BE CALLED FROM BASIC with SYS 4864!

Sooner or later, we all need to face this little gang we've been trying to avoid for decades, well...
I was thinking what's the best way to show it.
And perhaps this is the solution for this.

THESE TWO EXAMPLES ARE SHOWING YOU RESULTS in DECIMAL NUMBERS!
Much better than viewing graphical symbols, haha... You'll see exactly what you are dealing with!

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EXAMPLE: ASL - Arithmetic Shift Left = MULTIPLYING { by 2}
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	 This will multiply the accumulator value set in line $130d by 2
	 Calling it with SYS 4864 the 1st time will result in 2. 
	 Calling it the 2nd time, will result in 4, then 8, 16...
	 That is because we are copying the result and saving it back to the location,
	 to have it ready for the next multiplying proces when SYS 4864 is called.

	 In real life situation, you would just need to use ASL 2x in cases you would wanna multiply
	 the result with 4 {value of LDA #$06 * 2 * 2 }. LDA #$01, ASL, ASL

	 We are simulating this by executing the SYS 4864 several times.

. 01300  a9 00    lda #$00
. 01302  8d 00 ff sta $ff00
. 01305  a9 93    lda #$93
. 01307  20 d2 ff jsr $ffd2
. 0130a  20 42 c1 jsr $c142
. 0130d  a9 01    lda #$01
. 0130f  0a       asl
. 01310  8d e8 07 sta $07e8
. 01313  85 60    sta $60
. 01315  20 b4 b8 jsr $b8b4
. 01318  20 07 ba jsr $ba07
. 0131b  a9 00    lda #$00
. 0131d  a2 08    ldx #$08
. 0131f  a0 03    ldy #$03
. 01321  20 5d ba jsr $ba5d
. 01324  ad e8 07 lda $07e8
. 01327  8d 0e 13 sta $130e
. 0132a  60       rts

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EXAMPLE: LSR - Logical Shift Right = DIVIDE {by 2}
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The same as above, however in opposite direction.

. 01300  a9 00    lda #$00
. 01302  8d 00 ff sta $ff00
. 01305  a9 93    lda #$93
. 01307  20 d2 ff jsr $ffd2
. 0130a  20 42 c1 jsr $c142
. 0130d  a9 04    lda #$80
. 0130f  4a       lsr
. 01310  8d e8 07 sta $07e8
. 01313  85 60    sta $60
. 01315  20 b4 b8 jsr $b8b4
. 01318  20 07 ba jsr $ba07
. 0131b  a9 00    lda #$00
. 0131d  a2 08    ldx #$08
. 0131f  a0 03    ldy #$03
. 01321  20 5d ba jsr $ba5d
. 01324  ad e8 07 lda $07e8
. 01327  8d 0e 13 sta $130e
. 0132a  60       rts

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