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CHAPTER 7 DETAILED EXECUTION INSTRUCTIONS
7.62 LD (Load Word Data in Memory to Program Status Register)
Loads the word data at memory address "R15" to the program status (PS), and adds 4
to the value of "R15".
At the time this instruction is executed, if the value of the interrupt level mask register
(ILM) is in the range 16 to 31, only new "ILM" settings between 16 and 31 can be
entered. If data in the range 0 to 15 is loaded from memory, the value 16 will be added to
that data before being transferred to the "ILM". If the original "ILM" value is in the range
0 to 15, then any value from 0 to 31 can be transferred to the "ILM".
■ LD (Load Word Data in Memory to Program Status Register)
Assembler format: LD @ R15 +, PS
Operation: (R15) → PS
R15 + 4 → R15
Flag change:
N, Z, V, and C: Data is transferred from "R15".
Execution cycles: 1 + a + c cycles
The value of "c" is normally 1 cycle. However, if the next instruction involves read or write access
to memory address "R15", the system stack pointer (SSP) or the user stack pointer (USP), then an
interlock is applied and the value becomes 2 cycles.
Instruction format:
NZVC
CCCC
MSB LSB
0000011110010000