C8051F970-A-GM Datasheet, PDF (210/454 Pages) Silicon Laboratories – Low Power Capacitive Sensing MCU with up to 32 kB of Flash

C8051F97x
Table 22.3. MAC0 Unsigned Rounding without Saturation (SIGNEDEN = 0, SATURATE= 0)
41-Bit ACC Bits 15–0 41-Bit ACC Bits 31–16 Lower 16 Bits of MAC0 Upper 24 Bits of
(ACC41[15:0])
(ACC41[31:16])
Accumulator
MAC0 Accumulator
>0x8000
Any value
ACC41[31:16] + 1
All bits = 0
<0x8000
Any value
ACC41[31:16]
All bits = 0
== 0x8000
Odd (LSB == 1)
ACC41[31:16] + 1
All bits = 0
== 0x8000
Even (LSB == 0)
ACC41[31:16]
All bits = 0
Table 22.4. MAC0 Signed Rounding without Saturation
(SIGNEDEN = 1, SATURATE = 0, Let X41 = [ACC41 + 0x8000])
41-Bit ACC Bits 15–0
(ACC41[15:0])
>0x8000
<0x8000
== 0x8000
== 0x8000
41-Bit ACC Bits 31–16 Lower 15 Bits of MAC0 Upper 25 Bits of
(ACC41[31:16])
Accumulator
MAC0 Accumulator
Any value
X41[30:16]
All bits = X41[39]
Any value
X41[30:16]
All bits = X41[39]
Odd (LSB == 1)
X41[30:16]
All bits = X41[39]
Even (LSB == 0)
X41[30:16] - 1
All bits = X41[39]
When saturation bit SATURATE is set to 1, Table 22.5 and Table 22.6 show the saturation results.
Table 22.5. SIGNEDEN = 0, SATURATE = 1, Y40 = Unsaturated Rounded Result
(SOVF | HOVF) value
0
1
MAC0 Accumulator
Y40
0x000000FFFF
Table 22.6. SIGNEDEN = 1, SATURATE = 1, Z40 = Unsaturated Rounded Result
(SOVF | HOVF | (ACC41[31]^Z40[15])) Value
0
1, ACC41[39] = 0
1, ACC41[39] = 1
MAC0 Accumulator
Z40
0x0000007FFF
0xFFFFFF8000
Rev 1.0
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