Information Manual
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998
Instruction Set
Lucent Technologies Inc.
DRAFT COPY
4-9
4.4 Processor Flags
Control and special function instructions can be conditionally executed on the basis of internal flags set by the fol-
lowing conditions:
A previous ALU operation
A previous BMU operation
A previous special function instruction
The condition of one of the counters
The value of a randomly set bit
A test by the BIO port
An interrupt from the JTAG port
Functional operations on the accumulators set the flags as described above. Loading the accumulators with data
move instructions or multiply/ALU transfer statements does not set flags.
Four of the basic processor flags are defined below. They can be set by either ALU or BMU operations. These
flags and their meanings are given below:
LMI
Logical Minus—A logical minus is determined by the state of bit 35 of the accumulator after the last DAU or
BMU operation result. If bit 35 = 1, the result is a negative number and LMI is true.
LEQ
Logical Equal—A logical equal is determined by testing bits 35—0 of the last DAU or BMU operation
result. If these bits are all zero, the result is zero and LEQ is true.
LLV
Logical Overflow (36-bit Overflow)—LLV is true if the sign of the result of an operation cannot be repre-
sented in a 36-bit accumulator.
LMV
Mathematical Overflow (32-bit Overflow)—LMV is true if bit 31 of the accumulator differs from any of the
guard bits (32—35) after the last DAU or BMU operation. This indicates a number not representable in
32 bits.
Содержание DSP1611
Страница 18: ...Chapter 1 Introduction...
Страница 27: ...Chapter 2 Hardware Architecture...
Страница 52: ...Chapter 3 Software Architecture...
Страница 116: ...Chapter 4 Instruction Set...
Страница 154: ...Chapter 5 Core Architecture...
Страница 176: ...Chapter 6 External Memory Interface...
Страница 208: ...Chapter 7 Serial I O...
Страница 237: ...Chapter 8 Parallel I O DSP1617 Only...
Страница 261: ...Chapter 9 Parallel Host Interface PHIF DSP1611 18 27 28 29 Only...
Страница 275: ...Chapter 10 Bit I O Unit...
Страница 284: ...Chapter 11 JTAG Test Access Port...
Страница 306: ...Chapter 12 Timer...
Страница 313: ...Chapter 13 Bit Manipulation Unit...
Страница 325: ...Chapter 14 Error Correction Coprocessor DSP1618 28 Only...
Страница 350: ...Chapter 15 Interface Guide...
Страница 367: ...Appendix A Instruction Encoding...
Страница 379: ...Appendix B Instruction Set Summary...
Страница 381: ...aD extractz aS IM16 B 52 aD insert aS arM B 53 aD insert aS IM16 B 54 aD aS aaT B 55...
Страница 437: ...Index...