ADDRESSING MODES
A - 10
INSTRUCTION SET DETAILS
MOTOROLA
A.4
ADDRESSING MODES
The addressing modes are grouped into three categories: register direct, address regis-
ter indirect, and special. These addressing modes are summarized in Table A-2. All
address calculations are performed in the address ALU to minimize execution time and
loop overhead. Addressing modes, which specify whether the operands are in registers,
in memory, or in the instruction itself (such as immediate data), provide the specific
address of the operands.
The register direct addressing mode can be subclassified according to the specific regis-
ter addressed. The data registers include X1, X0, Y1, Y0, X, Y, A2, A1, A0, B2, B1, B0,
A, and B. The control registers include SR, OMR, SP, SSH, SSL, LA, LC, CCR, and MR.
Address register indirect modes use an address register Rn (R0–R7) to point to locations
in X, Y, and P memory. The contents of the Rn address register (Rn) is the effective
address (ea) of the specified operand, except in the “indexed by offset” mode where the
effective address (ea) is (Rn+Nn). Address register indirect modes use an address mod-
ifier register Mn to specify the type of arithmetic to be used to update the address regis-
ter Rn. If an addressing mode specifies an address offset register Nn, the given address
offset register is used to update the corresponding address register Rn. The Rn address
register may only use the corresponding address offset register Nn and the correspond-
ing address modifier register Mn. For example, the address register R0 may only use the
N0 address offset register and the M0 address modifier register during actual address
computation and address register update operations. This unique implementation allows
the user to easily address a wide variety of DSP-oriented data structures. All address
register indirect modes use at least one set of address registers (Rn, Nn, and Mn), and
the XY memory reference uses two sets of address registers, one for the X memory
space and one for the Y memory space.
The special addressing modes include immediate and absolute addressing modes as
well as implied references to the program counter (PC), the system stack (SSH or SSL),
and program (P) memory.
Addressing modes may also be categorized by the ways in which they can be used.
Table A-2 and Table A-3 show the various categories to which each addressing mode
belongs. These addressing mode categories may be combined so that additional, more
restrictive classifications may be defined. For example, the instruction descriptions may
use a
memory alterable
classification, which refers to addressing modes that are
both
memory addressing modes
and
alterable addressing modes. Thus, memory alterable
addressing modes use address register indirect and absolute addressing modes.
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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