ST ST10F276E - Page 92

Multiply-accumulate unit (MAC) UM0404
92/564 DocID13284 Rev 2
MAL (FE5Ch / 2Eh) SFR Reset Value: 0000h
MSW (FFDEh / EFh) SFR Reset Value: 0200h
Note: The MAC condition flags are evaluated if required by the instruction being executed. In
particular they are not affected by any instruction of the regular instruction set. In
consequence, their values may not be consistent with the Accumulator content. For
example, loading the Accumulator with MOV instructions will not modify the condition flags.
Bit Function
MAH MAC Unit Accumulator High (bits [31...16])
1514131211109876543210
MAL
RW
Bit Function
MAL MAC Unit Accumulator Low (bits [15...0])
1514131211109876543210
MIR - SL E SV C Z N MAE
R RWRWRWRWRWRW RW
Bit Function
MAE Accumulator Extension (bits [39:32])
N
Negative Flag
Set when the Accumulator is negative at the end of a MAC operation.
Z
Zero Flag
Set when the Accumulator is zero at the end of a MAC operation.
C
Carry Flag
Set when a MAC operation produces a carry or a borrow bit.
SV
Sticky Overflow Flag
Set when a MAC operation produces a 40-bit arithmetic overflow. It remains set until
it is explicitly reset by software.
E
Extension Flag
Set when MAE contains significant bits at the end of a MAC operation
SL
Sticky Limit Flag
Set when the result of a MAC operation is automatically saturated. Also used for
CoMIN, CoMAX instructions to indicate that the Accumulator has changed. It
remains set until it is explicitly reset by software.
MIR
MAC Interrupt Request
Set when the MAC Unit generates an interrupt request.