INSTRUCTION DESCRIPTIONS
A - 258
INSTRUCTION SET DETAILS
MOTOROLA
Operation:
Assembler Syntax:
D+r
➞
D (parallel move)
RND D (parallel move)
Description: Round the 56-bit value in the specified destination operand D and store the
result in the MSP portion of the destination accumulator (A1 or B1). This instruction uses
a convergent rounding technique. The contribution of the LS bits of the result (A0 and
B0) is rounded into the upper portion of the result (A1 or B1) by adding a rounding con-
stant to the LS bits of the result. The MSP portion of the destination accumulator con-
tains the rounded result which may be read out to the data buses.
The value of the rounding constant added is determined by the scaling mode bits S0 and
S1 in the system status register (SR). A “1” is added in the rounding position as shown
below:
Normal or “standard’’ rounding consists of adding a rounding constant to a given
number of LS bits of a value to produce a rounded result. The rounding constant
depends on the scaling mode being used as previously shown. Unfortunately, when
using a twos-complement data representation, this process introduces a positive bias in
the statistical distribution of the roundoff error.
RND
Round Accumulator
RND
Rounding
Rounding Constant
S1
S0
Scaling Mode
Position
55 - 25
24
23
22
21 - 0
0
0
No Scaling
23
0. . . .0
0
1
0
0. . . .0
0
1
Scale Down
24
0. . . .0
1
0
0
0. . . .0
1
0
Scale Up
22
0. . . .0
0
0
1
0. . . .0
Summary of Contents for DSP56K
Page 12: ...xii LIST of TABLES MOTOROLA List of Tables Continued Table Page Number Title Number ...
Page 13: ...MOTOROLA DSP56K FAMILY INTRODUCTION 1 1 SECTION 1 DSP56K FAMILY INTRODUCTION ...
Page 31: ...MOTOROLA DATA ARITHMETIC LOGIC UNIT 3 1 SECTION 3 DATA ARITHMETIC LOGIC UNIT ...
Page 50: ...DATA ALU SUMMARY 3 20 DATA ARITHMETIC LOGIC UNIT MOTOROLA ...
Page 51: ...MOTOROLA ADDRESS GENERATION UNIT 4 1 SECTION 4 ADDRESS GENERATION UNIT ...
Page 77: ...MOTOROLA PROGRAM CONTROL UNIT 5 1 SECTION 5 PROGRAM CONTROL UNIT ...
Page 124: ...INSTRUCTION GROUPS 6 30 INSTRUCTION SET INTRODUCTION MOTOROLA ...
Page 125: ...MOTOROLA PROCESSING STATES 7 1 SECTION 7 PROCESSING STATES STOP WAIT EXCEPTION NORMAL RESET ...
Page 167: ...STOP PROCESSING STATE MOTOROLA PROCESSING STATES 7 43 ...
Page 168: ...STOP PROCESSING STATE 7 44 PROCESSING STATES MOTOROLA ...
Page 169: ...MOTOROLA PORT A 8 1 SECTION 8 PORT A ...
Page 176: ...PORT A INTERFACE 8 8 PORT A MOTOROLA ...
Page 177: ...MOTOROLA PLL CLOCK OSCILLATOR 9 1 SECTION 9 PLL CLOCK OSCILLATOR x x d Φ VCO ...
Page 191: ...10 2 ON CHIP EMULATION OnCE MOTOROLA SECTION 10 ON CHIP EMULATION OnCE ...
Page 218: ...USING THE OnCE MOTOROLA ON CHIP EMULATION OnCE 10 29 ...
Page 604: ...INSTRUCTION ENCODING A 338 INSTRUCTION SET DETAILS MOTOROLA ...
Page 605: ...MOTOROLA BENCHMARK PROGRAMS B 1 APPENDIX B BENCHMARK PROGRAMS T T T T T P1 P3 P2 P4 T T T ...
Page 609: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 5 ...
Page 611: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 7 ...
Page 613: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 9 ...
Page 615: ...BENCHMARK PROGRAMS MOTOROLA BENCHMARK PROGRAMS B 11 ...