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TMP92CZ26A
92CZ26A-628
3.26 Multiply and Accumulate Calculation Unit (MAC)
The TMP92CZ26A includes a multiply-accumulate unit (MAC) capable of 32-bit × 32-bit + 64-bit
arithmetic operations at high speed. The MAC has the following features:
One-cycle execution for all MAC operations (excluding register access time)
Three operation modes : 1) 64-bit + 32-bit × 32-bit
2) 64-bit − 32-bit × 32-bit
3) 32-bit × 32-bit − 64-bit
Support for signed/unsigned operations
Support for integer operations only
3.26.1 Registers
The MAC in the TMP92CZ26A has one control register and three data registers. These
registers are connected to the CPU via a 32-bit bus and can be accessed in one system clock
(f
SYS
).
3.26.1.1 Control Register
The control register is used to control the operation of the MAC.
MAC Control Register
7 6 5 4 3 2 1 0
bit Symbol MOVF MOPST MSTTG2 MSTTG1 MSTTG0 MSGMD MOPMD1 MOPMD0
Read/Write R/W W R/W R/W R/W
After reset 0 0 0 0 0 0 0 0
Function
Overflow
flag
0: No
overflow
1: Overflow
occurred
Calculation
soft start
0:Don’t care
1:Start
calculation
Calculation start trigger
000: Write to MACMA<7:0>
001: Write to MACMB<7:0>
010: Write to MACMOR<7:0>
011: Write to MACMOR<39:32>
1xx: Write of “1” to <MOPST>
Sign mode
0: Unsigned
1: Signed
Calculation mode
00: 64 + 32×32
01: 64 − 32×32
10: 32×32 − 64
11: Reserved
Note 1: <MOPST> is write-only and it is read as “0”.
Note 2: Writing “1xx” to <MSTTG2:0> and writing “1” to <MOPST> can be executed in the same write cycle.
Note 3: <MOVF> is fixed two system clocks (f
SYS
) after calculation is started.
MACCR
(1BFCH)
Prohibit
Read-modify
-write