Using Computational Status
2-22
ADSP-BF535 Blackfin Processor Hardware Reference
RND12
,
RND
and
RND20
extract 16-bit values from bit 12, bit 16 and bit 20,
respectively, and perform biased rounding regardless of the state of the
RND_MOD
bit in
ASTAT
.
For example:
R3.L = R4 ( RND ) ;
performs biased rounding at bit 16, depositing the result in a half word.
R3.L = R4 + R5 ( RND12 ) ;
performs an addition of two 32-bit numbers, biased rounding at bit 12,
depositing the result in a half word.
R3.L = R4 + R5 ( RND20 ) ;
performs an addition of two 32-bit numbers, biased rounding at bit 20,
depositing the result in a half word.
Using Computational Status
The multiplier, ALU, and shifter update the overflow and other status
flags in the processor’s Arithmetic Status (
ASTAT
) register. To use status
conditions from computations in program sequencing, use conditional
instructions to test the
CC
flag (bit 5,
ASTAT
register) after the instruction
executes. This method permits monitoring each instruction’s outcome.
The
ASTAT
register is a 32-bit register, with some bits reserved. To ensure
compatibility with future implementations, writes to this register should
write back the values read from these reserved bits.
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...