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UM0404
Multiply-accumulate unit (MAC)
Program control
•
Repeat Unit allowing some MAC co-processor instructions to be repeated up to 8192
times. Repeated instructions may be interrupted.
•
MAC interrupt (Class B Trap) on MAC condition flags.
4.2 MAC
operation
Figure 16. MAC architecture
1.
* Shared with standard ALU.
Operand 2
Operand 1
Control Unit
Repeat Unit
ST10 CPU
Interrupt
Controller
MSW
MRW
MAH
MAL
MCW
Flags MAE
Mux
8-bit Left/Right
Shifter
Mux
Mux
Sign Extend
16 x 16
Concatenation
signed/unsigned
Multiplier
40-bit Signed Arithmetic Unit
0h
0h
08000h
40
16
40
40
32
32
16
40
40
40
40
40
Scaler
A
B
40
GPR Pointers *
IDX0 Pointer
IDX1 Pointer
QR0 GPR Offset Register
QR1 GPR Offset Register
QX0 IDX Offset Register
QX1 IDX Offset Register
Data
Limiter
(MA-bus)
(MB-bus)