Motorola ColdFire MCF5281 - Manual (Page 85)

Enhanced Multiply-Accumulate Unit (EMAC)
Freescale Semiconductor 3-7
Figure 3-4. Accumulator Registers (ACC0–3)
3.2.4 Accumulator Extension Registers (ACCext01, ACCext23)
Each pair of 8-bit accumulator extension fields are concatenated with the corresponding 32-bit
accumulator register to form the 48-bit accumulator. For more information, see
Section 3.3, “Functional
Description.”
Figure 3-5. Accumulator Extension Register (ACCext01)
BDM: 0x806 (ACC0)
0x809 (ACC1)
0x80A (ACC2)
0x80B (ACC3)
Access: User read/write
BDM read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R
Accumulator
W
Reset – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
Table 3-5. ACC0–3 Field Descriptions
Field Description
31–0
Accumulator
Store 32-bits of the result of the MAC operation.
BDM: 0x807 (ACCext01) Access: User read/write
BDM read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R
ACC0U ACC0L ACC1U ACC1L
W
Reset – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
Table 3-6. ACCext01 Field Descriptions
Field Description
31–24
ACC0U
Accumulator 0 upper extension byte
23–16
ACC0L
Accumulator 0 lower extension byte
15–8
ACC1U
Accumulator 1 upper extension byte
7–0
ACC1L
Accumulator 1 lower extension byte
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3