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Section 3 DSP Operation
Rev. 4.00 Sep. 14, 2005 Page 101 of 982
REJ09B0023-0400
IF
1
2
MOVX
MOVX
MOVX
MOVX & PADD
MOVX & PADD
MOVX & PADD
3
4
5
6
ID
EX
MA/DSP
PADD X0, Y0, A0
MOVX.W @(R4, R8), X0
MOVX.W @R4+, X0
Slot
Stage
Operation Sequence Example
Addressing
Addressing
Previous cycle result is used.
Figure 3.2 Operation Sequence Example
Every time an ALU arithmetic operation is executed, the DC, N, Z, V, and GT bits in DSR are
basically updated in accordance with the operation result. However, in case of a conditional
operation, they are not updated even though the specified condition is true and the operation is
executed. In case of an unconditional operation, they are always updated in accordance with the
operation result. The definition of a DC bit is selected by CS0 to CS2 (condition selection) bits in
DSR. The DC bit result is as follows:
Carry or Borrow Mode: CS[2:0] = 000: The DC bit indicates that carry or borrow is generated
from the most significant bit of the operation result, except the guard-bit parts. Some examples are
shown in figure 3.3. This mode is the default condition. When the input data is negative in a PABS
or PNEG instruction, carry is generated to add 1 to the LSB.
Example 1
Carry detecting point
Guard bits
Carry is detected
0000
0000
+)
0000
0000
1111
0000
1111
0000
1111
0000
1111
0001
0000 0001 0000 0000 0000 0000
Example 2
Carry detecting point
Guard bits
Carry is not detected
1111
0011
+)
1111
1111
0111
0001
0000
0000
0000
0000
0000
0000
0011
(1)
1110 1000 0000 0000 0000
Example 3
Borrow detecting point
Guard bits
Borrow is not detected
0000
0000
–)
0000
0000
0000
0000
0000
0000
0000
0000
0001
0001
0000 0000 0000 0000 0000 0000
Example 4
Borrow detecting point
Guard bits
Borrow is detected
0000
0000
–)
0000
0000
0001
0001
0000
0000
0000
0000
0001
0010
1111 1111 1111 1111 1111 1111
Figure 3.3 DC Bit Generation Examples in Carry or Borrow Mode
Summary of Contents for HD6417641
Page 2: ...Rev 4 00 Sep 14 2005 Page ii of l...
Page 7: ...Rev 4 00 Sep 14 2005 Page vii of l...
Page 11: ...Rev 4 00 Sep 14 2005 Page xi of l USB Universal serial bus WDT Watch dog timer...
Page 12: ...Rev 4 00 Sep 14 2005 Page xii of l...
Page 28: ...Rev 4 00 Sep 14 2005 Page xxviii of l...
Page 204: ...Section 4 Clock Pulse Generator CPG Rev 4 00 Sep 14 2005 Page 154 of 982 REJ09B0023 0400...
Page 212: ...Section 5 Watchdog Timer WDT Rev 4 00 Sep 14 2005 Page 162 of 982 REJ09B0023 0400...
Page 228: ...Section 6 Power Down Modes Rev 4 00 Sep 14 2005 Page 178 of 982 REJ09B0023 0400...
Page 246: ...Section 8 X Y Memory Rev 4 00 Sep 14 2005 Page 196 of 982 REJ09B0023 0400...
Page 318: ...Section 11 User Break Controller UBC Rev 4 00 Sep 14 2005 Page 268 of 982 REJ09B0023 0400...
Page 454: ...Section 12 Bus State Controller BSC Rev 4 00 Sep 14 2005 Page 404 of 982 REJ09B0023 0400...
Page 504: ...Section 14 U Memory Rev 4 00 Sep 14 2005 Page 454 of 982 REJ09B0023 0400...
Page 566: ...Section 17 Compare Match Timer CMT Rev 4 00 Sep 14 2005 Page 516 of 982 REJ09B0023 0400...
Page 868: ...Section 21 A D Converter Rev 4 00 Sep 14 2005 Page 818 of 982 REJ09B0023 0400...
Page 914: ...Section 23 I O Ports Rev 4 00 Sep 14 2005 Page 864 of 982 REJ09B0023 0400...
Page 956: ...Section 24 List of Registers Rev 4 00 Sep 14 2005 Page 906 of 982 REJ09B0023 0400...
Page 1016: ...Section 25 Electrical Characteristics Rev 4 00 Sep 14 2005 Page 966 of 982 REJ09B0023 0400...
Page 1024: ...Appendix Rev 4 00 Sep 14 2005 Page 974 of 982 REJ09B0023 0400...
Page 1032: ...Rev 4 00 Sep 14 2005 Page 982 of 982 REJ09B0023 0400 X X Y data addressing 52 X Y memory 193...
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