HD6417641 RENESAS [Renesas Technology Corp], HD6417641 Datasheet - Page 154

• Manufacturer Part Number: HD6417641
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 3 DSP Operation
3.1.2
Figure 3.6 shows the ALU integer arithmetic operation flow. Table 3.3 shows the variation of this
type of operation. The correspondence between each operand and registers is the same as ALU
fixed-point operations as shown in table 3.2.
Table 3.3
Note: The ALU integer operations are basically 24-bit operation, the upper 16 bits of the base
Rev. 4.00 Sep. 14, 2005 Page 104 of 982
REJ09B0023-0400
Mnemonic
PINC
PDEC
precision and 8 bits of the guard bits parts. So the signed bit is copied to the guard-bit parts
when a register not providing the guard-bit parts is specified as the source operand. When
a register not providing the guard-bit parts is specified as a destination operand, the upper
word excluding the guard bits of the operation result are input into the destination register.
ALU Integer Operations
Variation of ALU Integer Operations
39
Guard
Ignored
Cleared
Function
Increment by 1
Decrement by 1
Figure 3.6 ALU Integer Arithmetic Operation Flow
31
Source 1
39
Guard
31
Destination
Source 1
Sx
+1
Sx
−1
0
ALU
39
Guard
31
Source 2
Source 2
+1
Sy
−1
Sy
0
GT
Z
DSR
N
V
0
DC
Destination
Dz
Dz
Dz
Dz