
6 FUNCTIONS
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EPSON
S1C33 FAMILY C33 PE CORE MANUAL
6.3.9 Undefined Instruction Exception
When an instruction, which does not exist in the C33 PE instruction set, is executed, an undefined instruction
exception occurs. The object code is loaded into the 16 low-order bits of the IDIR register and is processed similar
to the
nop instruction. In this case, the PC value that is saved into the stack by the exception processing is the
instruction address that follows the undefined instruction executed.
Address TTBR + 12 is used to store the undefined instruction exception vector.
6.3.10 ext Exception
If three or more ext instructions are described sequentially, an ext exception occurs when the third ext
instruction is detected. In this case, the PC value that is saved into the stack by the exception processing is the first
ext instruction address.
Address TTBR + 8 is used to store the
ext exception vector.
When an instruction, which does not support the extension in the ext instruction, follows an ext, the ext
instruction will be executed as a
nop instruction.
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