ADDRESSING
4 - 20
ADDRESS GENERATION UNIT
MOTOROLA
as 0, 32, 64, 96, 128, 160, etc. For this example, L is arbitrarily chosen to be 2, making
the lower boundary 64. The upper boundary of the buffer is then 84 (the lower boundary
plus 20 (M–1)). The Mn register is loaded with the value 20 (M–1). The offset register is
arbitrarily chosen to be 15 (Nn
≤
M). The address pointer is not required to start at the lower
address boundary and can begin anywhere within the defined modulo address range —
i.e., within the lower bo (2
k
) address region. The address pointer, Rn, is arbitrarily
chosen to be 75 in this example. When R2 is post-incremented by the offset by the MOVE
instruction, instead of pointing to 90 (as it would in the linear mode) it wraps around to 69.
If the address register pointer increments past the upper boundary of the buffer (base ad-
dress plus M–1), it will wrap around to the base address. If the address decrements past
the lower boundary (base address), it will wrap around to the base address plus M–1.
If Rn is outside the valid modulo buffer range and an operation occurs that causes Rn to
be updated, the contents of Rn will be updated according to modulo arithmetic rules. For
example, a MOVE B0,X:(R0)+ N0 instruction (where R0=6, M0=5, and N0=0) would ap-
parently leave R0 unchanged since N0=0. However, since R0 is above the upper
boundary, the AGU calculates R0+ N0–M0–1 for the new contents of R0 and sets R0=0.
(Rn)
±
Nn MOD M
WHERE Nn = 2
k
(i.e., P = 1)
M
M
2
k
2
k
Figure 4-12 Linear Addressing with a Modulo Modifier
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 ...