SH7720 Datasheet, PDF (199/1524 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series

Section 3 DSP Operating Unit
3.5.8 Shift Operations
Shift operations can use either register or immediate value as the shift amount operand. Other
source and destination operands are specified by the register. There are two kinds of shift
operations of arithmetic and logical shifts. Table 3.27 shows the variation of this type of operation.
The correspondence between each operand and registers, except for immediate operands, is the
same as the ALU fixed-point operations as shown in table 3.21.
Table 3.27 Variation of Shift Operations
Mnemonic
Function
PSHA Sx, Sy, Dz Arithmetic shift
PSHL Sx, Sy, Dz Logical shift
PSHA #Imm1, Dz Arithmetic shift with
immediate.
PSHL #Imm2, Dz Logical shift with
immediate.
Source 1
Sx
Sx
Dz
Source 2
Sy
Sy
Imm1
Destination
Dz
Dz
Dz
Dz
Imm2
Dz
–32 <= Imm1 <= +32, –16 <= Imm2 <= +16
(1) Arithmetic Shift
Figure 3.17 shows the arithmetic shift operation flow.
39 32 31
Left shift
16 15
0
0
Shift out
39
Shift amount data
(source 2)
>=0
<0
32 31
+32 to -32
23 22 16 15
Sy
60
Imm1
39 32 31
(MSB copy)
Updated
0
Right shift
16 15
0
Shift out
DSR
GT Z N V DC
Ignored
Figure 3.17 Arithmetic Shift Operation Flow
Rev. 3.00 Jan. 18, 2008 Page 137 of 1458
REJ09B0033-0300