HD6417615 Hitachi Semiconductor, HD6417615 Datasheet - Page 78

• Manufacturer Part Number: HD6417615
• Description: Hardware Manual
• Manufacturer: Hitachi Semiconductor

An example of modulo addressing is indicated below:
The R4 register changes as follows due to the above settings.
Data is placed so that the upper 16 bits of the modulo start and end addresses become identical.
This is so because the modulo start address replaces only the lower 15 bits of the address register,
excepting bit 0.
Note: When using add index with DSP data addressing, there are cases where the value is
60
MS=H'E008; ME=H'E00C; R4=H'1000E008;
DMX=1; DMY=0;
Inc.
Inc.
Inc.
31
+2
+0
exceeded without the address pointer matching the ME. In such cases, the address pointer
does not return to the modulo start address. Bit 0 is disregarded not only for modulo
addressing, but also during X, Y data addressing, so always write 0 to the 0 bits of the
address pointer, index register, MS, and ME.
R8[Ix]
R4: H'1000E008
R4: H'1000E00A
R4: H'1000E00C
R4: H'1000E008
ALU
(sets modulo addressing for address register Ax (R4, R5))
0
31
15
R4[Ax]
R5[Ax]
XAB
ABx
16
Figure 2.11 Modulo Addressing
(becomes the modulo start address because the modulo end
address occurred)
15
Instruction (MOVX/MOVY)
0
1
DMX
15
15
CONT
CMP
ME
MS
DMY
1
1
31
15
R6[Ay]
R7[Ay]
16
YAB
ABy
15
0
1
AU
31
R9[Iy]
+0
+2
0