Motorola 24-Bit Digital Signal Processor, DSP56000 manual Program Control Instructions, Debug, Jmp

INSTRUCTION GROUPS

	OPCODE/OPERANDS			PARALLEL MOVE EXAMPLES
IMMEDIATE SHORT DATA		ADD	X0,A		#$05,Y1
ADDRESS REGISTER UPDATE		ADD	X0,A		(R0)+N0
REGISTER TO REGISTER		ADD	X0,A		A1,Y0
X MEMORY		ADD	X0,A		X0,X:(R3)+
X MEMORY PLUS REGISTER		ADD	X0,A		X:(R4)–,X1	A,Y0
Y MEMORY		ADD	X0,A		Y:(R6)+N6,X0
Y MEMORY PLUS REGISTER		ADD	X0,A		A,X0	B,Y:(R0)

NOTE: Parallel Move Syntax—Source(Src), Destination(Dst)

Figure 6-15 Classifications of Parallel Data Moves

contents of the 56-bit registers A and B were rounded to 24 bits before moving to the 24- bit memory registers.

The DSP offers parallel processing of the data ALU, AGU, and program control unit. For the instruction word above, the DSP will perform the designated operation (data ALU), the data transfers specified with address register updates (AGU), and will decode the next instruction and fetch an instruction from program memory (program control unit) all in one instruction cycle. When an instruction is more than one word in length, an additional instruction execution cycle is required. Most instructions involving the data ALU are reg- ister based (all operands are in data ALU registers), thereby allowing the programmer to keep each parallel processing unit busy. An instruction that is memory oriented (such as a bit manipulation instruction) or that causes a control-flow change (such as a JMP) pre- vents the use of parallel processing resources during its execution.

6.4.6 Program Control Instructions

The program control instructions include jumps, conditional jumps, and other instructions affecting the PC and SS. Program control instructions may affect the CCR bits as speci- fied in the instruction. Optional data transfers over the XDB and YDB may be specified in some of the program control instructions. The following list contains the program control instructions:

DEBUG	Enter Debug Mode
DEBUGcc	Enter Debug Mode Conditionally
IIl	Illegal Instruction
Jcc	Jump Conditionally
JMP	Jump

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