Samsung KS57C2308 manual Display LD, ORG 01FDH, 01FFH LDC

KS57C2308/P2308/C2316/P2316 SAM47 INSTRUCTION SET

LDC — Load Code Byte

LDC(Continued)

Examples: 2. The following instructions will load one of four values defined by the define byte (DB) directive to the extended accumulator:

ORG 0500

DB 66H

DB 77H

DB 88H

DB 99H

DISPLAY LD	WX,#00H
LDC	EA,@WX	; EA ← address 0500H = 66H
RET

If the instruction “LDWX,#01H” is executed in place of “LD WX,#00H”, then

EA ← address 0501H = 77H.

If the instruction “LD WX,#02H” is executed in place of “LD WX,#00H”, then

EA ← address 0502H = 88H.

3.Normally, the LDC EA, @EA and the LDC EA, @WX instructions reference the table data on the page on which the instruction is located. If, however, the instruction is located at address xxFFH, it will reference table data on the next page. In this example, the upper 4 bits of the address at location 0200H is loaded into register E and the lower 4 bits into register A:

	ORG	01FDH
01FDH	LD	WX,#00H
01FFH	LDC	EA,@WX ; E ← upper 4 bits of 0200H address

;A ← lower 4 bits of 0200H address

4.Here is another example of page referencing with the LDC instruction: ORG 0100

DB	67H
SMB	0
LD	HL,#30H	;	Even number
LD	WX,#00H
LDC	EA,@WX	;	E ← upper 4 bits of 0100H address
		;	A ← lower 4 bits of 0100H address
LD	@HL,EA	;	RAM (30H) ← 7, RAM (31H) ← 6

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