ADSP-BF53x/BF56x Blackfin Processor Programming Reference
C-11
Instruction Opcodes
Opcode Representation In Listings, Memory
Dumps
The Blackfin assembler produces opcodes in little endian format for mem-
ory storage. Little endian format is efficient for instruction fetching, but
not especially convenient for user readability. Each 16 bits of opcode are
stored in memory with the least significant byte first followed by the most
significant byte in the next higher address.
32-bit opcodes appear in memory as the most significant 16 bits first, fol-
lowed by the least significant 16 bits at the next higher address. The
reason is that the instruction length is encoded in the most significant 16
bits of the opcode. By storing this information in the lower addresses, the
Program Sequencer can determine in one fetch whether it can begin pro-
cessing the current instruction right away or must wait to fetch the
remainder of the instruction first.
Table C-7. Sample Opcode Holes Representation
Instruction
and Version
Bin
Opcode Range 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Zero Overhead Loop Setup
0xE080 0000—
0xE08F 03FF
1 1 1 0 0 0 0 0 1 0 0 0
pcrel5m2
divided by 2
0 0 0 0 0 0
pcrel11m2 divided by 2
LOOP loop_name LC0
LOOP_BEGIN loop_name
LOOP_END loop_name
... is mapped to...
LSETUP ( pcrel5m2, pcrel11m2 ) LC0
... where the address of LOOP_BEGIN determines pcrel5m2, and the address of LOOP_END deter-
mines pcrel11m2.
Summary of Contents for ADSP-BF53x Blackfin
Page 38: ...Conventions xxxviii ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 134: ...System Reset and Powerup 3 18 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 486: ...Instruction Overview 13 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 512: ...Instruction Overview 14 26 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 604: ...Instruction Overview 15 92 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 688: ...Instruction Overview 18 48 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 742: ...Instruction Overview 19 54 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 752: ...Examples 20 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 790: ...ADSP BF535 Flags A 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 800: ...Performance Monitor Registers B 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 1042: ...Index I 40 ADSP BF53x BF56x Blackfin Processor Programming Reference...