Exam 2 Embedded Systems Abichar UCF || 100% Accurate
Answers.
MSP430 little endian or big endian? correct answers little endian
Status Register (R2) bits (0-4) correct answers GIE (3) ; N (2) ; Z(1) ; C(0)
4 Addressing Modes and their bits correct answers Register Mode -> R4 (00)
Indexed Mode -> 0(R4) (01)
Indirect Register -> @R4 (10)
Indirect Register AutoInc -> @R4+ (11)
Disguised Address Mode Representations correct answers #16 -> @PC+
#1 -> 0(R3)
VAR1 (source) -> [Address - PC - 2](PC)
VAR2 (destination) -> [Address - PC - 4](PC)
@VAR1 (S/D) -> [its address](R2)
Why does source have more flexibility whereas destination can only be 2 representations?
correct answers We read more than we write
Does PC move during an instruction? correct answers yes so we should avoid PC relative such as
120(PC) for example
Signed Jump Formats correct answers JGE (greater or equal)
JL (jump if less)
Unsigned Jump Formats correct answers JC / JHZ
JNC (jump if not carry)/ JLO (jump if lower)
Generally, the # of cycles for execution is... correct answers equal to the # of memory accesses
(read or write), but doesn't add to cycle count for register read or write
Difference between RLA and RLC correct answers RLA brings left-most bit to Carry and always
brings 0 to right-most bit. RLC brings left-most bit to Carry and always brings Carry to right-
most bit
Difference between RRA and RRC correct answers RRA repeats left-most bit as shifted right
and brings right-most bit to the Carry. RRC always puts RIGHT-most bit into Carry and the
Carry bit into the left-most bit
Right-most bit of PC is always... correct answers 0
@PC+ is used for... correct answers immediate values (#14, #200). Basically anything that isn't
1,2,4, or 8.
Answers.
MSP430 little endian or big endian? correct answers little endian
Status Register (R2) bits (0-4) correct answers GIE (3) ; N (2) ; Z(1) ; C(0)
4 Addressing Modes and their bits correct answers Register Mode -> R4 (00)
Indexed Mode -> 0(R4) (01)
Indirect Register -> @R4 (10)
Indirect Register AutoInc -> @R4+ (11)
Disguised Address Mode Representations correct answers #16 -> @PC+
#1 -> 0(R3)
VAR1 (source) -> [Address - PC - 2](PC)
VAR2 (destination) -> [Address - PC - 4](PC)
@VAR1 (S/D) -> [its address](R2)
Why does source have more flexibility whereas destination can only be 2 representations?
correct answers We read more than we write
Does PC move during an instruction? correct answers yes so we should avoid PC relative such as
120(PC) for example
Signed Jump Formats correct answers JGE (greater or equal)
JL (jump if less)
Unsigned Jump Formats correct answers JC / JHZ
JNC (jump if not carry)/ JLO (jump if lower)
Generally, the # of cycles for execution is... correct answers equal to the # of memory accesses
(read or write), but doesn't add to cycle count for register read or write
Difference between RLA and RLC correct answers RLA brings left-most bit to Carry and always
brings 0 to right-most bit. RLC brings left-most bit to Carry and always brings Carry to right-
most bit
Difference between RRA and RRC correct answers RRA repeats left-most bit as shifted right
and brings right-most bit to the Carry. RRC always puts RIGHT-most bit into Carry and the
Carry bit into the left-most bit
Right-most bit of PC is always... correct answers 0
@PC+ is used for... correct answers immediate values (#14, #200). Basically anything that isn't
1,2,4, or 8.
