NXP Semiconductors MPC5644A Reference Manual page 939

BINV also selects between adc or sbc enhanced ALU operation, using inverted C flag as carry-in besides
BS inversion for sbc. Note that BINV does not invert carry in fixed-carry operations (see
Section Table 24-87., ALU Carry-In
When BINV = 0, T4BBS = 111 and CIN = 0, the value assigned to BS is 0x800000, instead of 0x0. See
Section , Generating "max"
24.5.9.2.5 Carry-in Control
CIN field (1 bit, Table 24-87) controls the carry-in for addition/subtraction operations. Functionality of
CIN field depends on the arithmetic operation selected by ALUOP. When ALUOP is not available in
microinstruction, the operation selected is add. For carry-in control in MDU operations, see
Operation
add (addition)
adc (addition with carry)
sbc (subtraction with borrow)
1
Except on max-constant selection, see
2
Selected by ALUOP = 11000 and BINV = 1
3
Selected by ALUOP = 11000 and BINV = 0
Generating "max" constant
When T4BBS = 111, CIN = 0 and BINV = 0, BS is assigned to 0x800000 (called "max constant") instead
of 0x000000. This is an exception for CIN and BINV fields: when "max constant" is selected, the carry in
is 0 and B-source ("max constant" itself) is not inverted, neither the carry out.
"Max constant" is the value which, added to a time base value minus 1, gives the farthest wrapped time
base value that satisfies a channel greater-equal comparison. See
more information.
24.5.9.2.6 Shift operations
There are three types of shift operations: ALU, post-ALU and Shift Register. ALU shift operations are
covered in Section 24.5.9.2.10, ALU/MDU Operation
in the following sections.
Freescale Semiconductor
Table 24-86. B-Source Inversion – BINV
BINV
0 invert B-source
1 keep B-source bus unchanged
1
Except on max-constant selection, see
"max" constant.
Control).
constant, for more details.
Table 24-87. ALU Carry-In Control
2
3
Section , Generating "max"
MPC5644A Microcontroller Reference Manual, Rev. 6
Enhanced Time Processing Unit (eTPU2)
Meaning
1
Section , Generating
CIN = 0
1
carry-in used is 1
carry-in used is C flag
carry-in used is inverted C flag
constant.
Section 24.5.5, Enhanced
Selection. Post-ALU and Shift Register are covered
Table 24-70.
CIN = 1
carry-in used is 0
Channels, for
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