INSTRUCTION DESCRIPTIONS

MOVE

Move Data

MOVE

When a 56-bit accumulator (A or B) is specified as a destination operand D, any 24-bit source data to be moved into that accumulator is automatically extended to 56 bits by sign extending the MS bit of the source operand (bit 23) and appending the source oper- and with 24 LS zeros. Similarly, any 48-bit source data to be loaded into a 56-bit accu- mulator is automatically sign extended to 56 bits. Note that for 24-bit source operands both the automatic sign-extension and zeroing features may be disabled by specifying the destination register to be one of the individual 24-bit accumulator registers (A1 or B1). Similarly, for 48-bit source operands, the automatic sign-extension feature may be disabled by using the long memory move addressing mode and specifying A10 or B10 as the destination operand.

Note that the symbols used in decoding the various opcode fields of an instruction or par- allel move are completely arbitrary. Furthermore, the opcode symbols used in one instruction or parallel move are completely independent of the opcode symbols used in a different instruction or parallel move.

MOTOROLA

INSTRUCTION SET DETAILS

A - 161

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Motorola DSP56000, 24-Bit Digital Signal Processor manual Move