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2.2.3 Initial Register Values
When the CPU is reset, the program counter (PC) is initialized to the value stored at address H'0000
in the vector table, and the I bit in the CCR is set to 1. The other CCR bits and the general registers
are not initialized. In particular, the stack pointer (R7) is not initialized. The stack pointer should be
initialized by software, by the first instruction executed after a reset.
2.3 Data Formats
The H8/300L CPU can process 1-bit data, 4-bit (BCD) data, 8-bit (byte) data, and 16-bit (word)
data.
•
Bit manipulation instructions operate on 1-bit data specified as bit n in a byte operand
(n = 0, 1, 2, ..., 7).
•
All arithmetic and logic instructions except ADDS and SUBS can operate on byte data.
The MOV.W, ADD.W, SUB.W, CMP.W, ADDS, SUBS, MULXU (8 bits × 8 bits), and
•
DIVXU (16 bits ÷ 8 bits) instructions operate on word data.
•
The DAA and DAS instructions perform decimal arithmetic adjustments on byte data in packed
BCD form. Each nibble of the byte is treated as a decimal digit.
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