Information Manual
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998
Instruction Set
Lucent Technologies Inc.
DRAFT COPY
4-19
4.5 Instruction Set
(continued)
4.5.4 Special Function Group
Instructions from the special function group are always executed in one instruction cycle. They require one word of
program memory. The special function instructions are used to implement a number of algorithms that include the
following nonlinear functions: absolute value, signum, minimum and maximum value finder, A-law and µ-law con-
versions, division, half-wave and full-wave rectification, and rounding. Special function instructions are executed
either conditionally or unconditionally. Both the condition and its complement are available for use in special func-
tion instructions. Instructions from this group can be used in the cache.
The special function instructions can be conditioned on the basis of the flags defined in
. The result of the
most recent accumulator or BMU operation prior to the special function instruction establishes the state of the flags
for the conditions associated with logical or mathematical functions.
To write a special function instruction unconditionally, write F2 by itself (see
Table 4-10
). To write the special func-
tion instructions conditionally, write the full form—if CON F2. To use the event counter, write ifc CON F2—mean-
ing:
if CON is true then {
c1=c1+1
F2 instruction
c2=c1
}
else {
c1=c1+1
}
Note: If using the event counter (ifc instruction) and if the condition field CON is c0lt or c0ge, c0 is not incre-
mented. Otherwise, if using the event counter (ifc instruction) and if CON is c1lt or c1ge, c1 is incremented
once after the test. For example, ifc c0lt a0 = a1 first tests to see if c0 is less than zero, then increments
c1. If c0 is less than zero, a0 = a1 is executed and c2 is set to the new value of c1. If c0 is
≥
0, no further
action occurs. Normally, a test of c0, such as if c0lt goto 0x400, increments c0. In the case of the ifc c0lt
F2 instruction, c0 is not incremented.
Special Function Instructions
if CON F2
ifc CON F2
F2
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...