Motorola 24-Bit Digital Signal Processor, DSP56000 manual Source, Omr Ssl

INSTRUCTION DESCRIPTIONS

DO	Start Hardware Loop
Instruction Format:
DO	S, expr

Opcode:

DO

	23	20	19	16	15	8	7	0
0 0 0 0			0 1 1 0		1 1 D D	D D D D	D 0 0 0	0 0 0 0

ABSOLUTE ADDRESS EXTENSION

Instruction Fields:

S=6-bit Source operand = DDDDDD,

expr=16-bit Absolute Address in 24-bit extension word

							S
Source	D D		D	D	D	D	S/L	Source	D	D	D	D	D	D
X0	0	0	0	1	0	0	no	SR	1	1	1	0	0	1
X1	0	0	0	1	0	1	no	OMR	1	1	1	0	1	0
Y0	0	0	0	1	1	0	no	SP*	1	1	1	0	1	1
Y1	0	0	0	1	1	1	no	SSL**	1	1	1	1	0	1
A0	0	0	1	0	0	0	no	LA	1	1	1	1	1	0
B0	0	0	1	0	0	1	no	LC	1	1	1	1	1	1
A2	0	0	1	0	1	0	no	R0-R7	0	1	0	r	r	r
B2	0	0	1	1	0	0	no	N0-N7	0	1	1	n	n	n
A1	0	0	1	1	0	1	no	M0-M7	1	0	0	m m m
A	0	0	1	1	1	0	yes [see Notes on page A-97]
B	0	0	1	1	1	1	yes [see Notes on page A-97]
where rrr=Rn register
where nnn=Nn register
where mmm=Mn register
*For DO		SP, expr			The actual value that will be loaded into the loop counter (LC) is
					the value of the stack pointer (SP) before the execution of the

DO instruction, incremented by 1.

Thus, if SP=3, the execution of the DO SP,expr instruction will load the loop counter (LC) with the value LC=4.

**For DO SSL, expr The loop counter (LC) will be loaded with its previous value which was saved on the stack by the DO instruction itself.

A - 96 INSTRUCTION SET DETAILS MOTOROLA