HD6417641 RENESAS [Renesas Technology Corp], HD6417641 Datasheet - Page 186

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

Section 3 DSP Operation
MS and ME are set to specify the start and end addresses, and then later to set the DMX or DMY
bit to 1.
When the X/Y data transfer instruction set in DMX/DMY is executed, the address register
contents before update are compared with ME*
in the address register as the updated value*
specified for the X/Y data transfer instruction, the address pointer will not return to modulo start
address MS even though the address register contents match ME.
Notes: 1. Bits 1 to 15 of the address register are used for comparison. Though ME retains its
The maximum modulo size is 64-kbytes. This is sufficient for accessing the X or Y data memory.
Figure 3.21 shows a block diagram of modulo addressing.
Rev. 4.00 Sep. 14, 2005 Page 136 of 982
REJ09B0023-0400
31
+2
+0
2. The MS value is stored in bits 1 to 15 of the address register. Though MS retains its
R8 [Ix]
previous value for bit 0, 0 must always be written to bit 0.
previous value for bit 0, 0 must always be written to bit 0.
0
ALU
31
15
R4 [Ax]
R5 [Ax]
1615
XAB
ABx
Figure 3.21 Modulo Addressing
1
0
Instr (MOVX/Y)
2
15
15
15
DMX DMY
. If non-update address register addressing is
CONT
CMP
1
MS
ME
. If they match, modulo start address MS is stored
1
1
1
31
15
R6 [Ay]
R7 [Ay]
1615
YAB
ABx
1
0
AU
31
R9 [Iy]
+2
+0
0