Cypress PSoC CY8CTMG20 Series, Technical Reference Manual

Page: 31 / 308

PSoC CY8CTMG20x and CY8CTST200 TRM, Document No. 001-53603 Rev. *C 31
CPU Core (M8C)
2.5.3 Three-Byte Instructions
The three-byte instruction formats are the second most
prevalent instruction formats. These instructions need three
bytes because they either move data between two
addresses in the user accessible address space (registers
and RAM) or they hold 16-bit absolute addresses as the
destination of a long jump or long call.
The first instruction format, shown in the first row of
Table 2-5 , is used by the
LJMP
and
LCALL
instructions.
These instructions change program execution uncondition-
ally to an absolute address. The instructions use an 8-bit
opcode, leaving room for a 16-bit destination address.
The second three-byte instruction format, shown in the sec-
ond row of
Table 2-5 , is used by the following two address-
ing modes:
■
Destination Direct Source Immediate (
ADD [7], 5
)
■
Destination Indexed Source Immediate
(
ADD [X+7], 5
)
The third three-byte instruction format, shown in the third
row of
Table 2-5 , is for the Destination Direct Source Direct
addressing mode, which is used by only one instruction.
This instruction format uses an 8-bit opcode followed by two
8-bit addresses. The first address is the destination address
in RAM, while the second address is the source address in
RAM. The following is an example of this instruction:
MOV [7], [5]
Table 2-5. Three-Byte Instruction Formats
Byte 0 Byte 1 Byte 2
8-Bit Opcode 16-Bit Address (MSB, LSB)
8-Bit Opcode 8-Bit Address 8-Bit Data
8-Bit Opcode 8-Bit Address 8-Bit Address
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