16 bit Assembly

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SUB   - Subtract Instruction

The SUB instruction subtracts the second operand from the first operand.
This command has 3 parts, Instruction, then either a Register, Immediate value or a memory address.

Assembly Sample	Description	16 bit Machine Code
SUB AL, 0x03	;  8 bit immediate from AL	2C 03
SUB AX, 0x0303	;  16 bit immediate from AX	2D 03 03
SUB CL, 0x03	;  8 bit immediate from an 8 bit Register	80 E9 03
SUB CX, 0x03	;  8 bit immediate from 16 bit Register	83 E9 03
SUB CX, 0x0303	;  16 bit immediate from a Register	81 E9 03 03
SUB CL, AL	;  8 bit Register from 8 bit Register	2A C8
SUB CX, AX	;  16 bit Register from 16 bit Register	2B C8
SUB [BX], 0x03	;  8 bit immediate from memory address	83 2F 03
SUB [BX], 0x0303	;  16 bit immediate from memory address	81 E9 03 03
SUB [BX+2], 0x0033	;  16 bit Immediate from memory address	81 6F 02 23 00
SUB AX, [BX]	;  Memory address from 16 bit Register	2B 07
SUB [BX], AX	;  16 bit Register from memory address	29 07
SUB AX, [BX+2]	;  16 bit Register from memory address	2B 47 02
SUB [BX+2], AX	;  16 bit Register from memory address	29 47 02

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Last Update 07/02/2023