A.4.4 Condition Code Summary By Instruction; Table A-8 Notation Used For The Condition Code Summary Table - Motorola DSP56800 Manual

The value of the CC bit does not affect condition code computation for the TSTW instructions. These
instructions operate independently of the CC bit and correctly generate both signed and unsigned condition
codes.
The CC bit only affects operations in the data ALU, not operations performed in other blocks. These
include move instructions, bit-manipulation instructions, and address calculations performed by the AGU.
A.4.4 Condition Code Summary by Instruction
Table A-9 provides a detailed view of the condition codes affected by each instruction, and the
circumstances under which each condition code is set or cleared. Table A-8 describes the notation used.
Items in the "Notes" column of Table A-9 are explained immediately following the table on page A-15.
Table A-8. Notation Used for the Condition Code Summary Table
Notation
* Set by the result of the operation according to the standard definition.
— Not affected by the operation.
*16 Set according to the standard definition for 16-bit results.
*32 Set according to the standard definition for 32-bit results.
*36 Set according to the standard definition for 36-bit results.
*A Set by the result of the operation according to the size of destination.
*B Set by the result of the operation according to the size of destination.
=0 Cleared.
=1 Set.
? Set according to the special computation defined for the operation.
(number) Set according to the special computation defined by the note with the corresponding number.
The notes may be found immediately after Table A-9.
C L bit can be set if overflow has occurred in result.
T L bit can be set if limiting occurs when reading an accumulator during a parallel move or by the
instruction itself. An example of the latter case is
A accumulator before performing the bit-manipulation operation.
CT L bit can be set if overflow has occurred in the result or if limiting occurs when an accumulator is
being read.
The condition code computation shown in Table A-9 may differ from that defined in the opcode
descriptions; see Section A.7, "Instruction Descriptions." This indicates that the standard definition may be
used to generate the specific condition code result. For example, the Z flag computation for the CLR
instruction is shown as the standard definition, while the opcode description indicates that the Z flag is
always set. Table A-9 gives the chip implementation viewpoint, while the opcode descriptions give the
user viewpoint.
A-12
Description
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DSP56800 Family Manual
, which must first read the