DATA ALU PROGRAMMING MODEL
MOTOROLA
DATA ARITHMETIC LOGIC UNIT
3 - 19
3.5
DATA ALU PROGRAMMING MODEL
The Data ALU features 24-bit input/output data registers that can be concatenated to ac-
commodate 48-bit data and two 56-bit accumulators, which are segmented into three 24-
bit pieces that can be transferred over the buses. Figure 3-14 illustrates how the registers
in the programming model are grouped.
3.6
DATA ALU SUMMARY
The Data ALU performs arithmetic operations involving multiply and accumulate opera-
tions. It executes all instructions in one machine cycle and is not pipelined. The two 24-bit
numbers being multiplied can come from the X registers (X0 or X1) or Y registers (Y0 or
Y1). After multiplication, they are added (or subtracted) with one of the 56-bit accumula-
tors and can be convergently rounded to 24 bits. The convergent-rounding forcing
function detects the $800000 condition in the LSP and makes the correction as neces-
sary. The final result is then stored in one of the accumulators as a valid 56-bit number.
The condition code bits are set based on the rounded output of the logic unit.
47
0
55
0
55
0
DATA ALU
X0
23
0 23
0
47
0
Y1
Y0
23
0 23
0
DATA ALU
*
A2
A1
A0
23
8 7 0 23
0 23
0
*
B2
B1
B0
23
8 7 0 23
0 23
0
X1
INPUT REGISTERS
ACCUMULATOR REGISTERS
*Read as sign extension bits, written as don’t care.
X
Y
A
B
Figure 3-14 DSP56K Programming Model
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 ...
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