Renesas H8S Series Hardware Manual page 71

Table 2-5 Absolute Address Access Ranges
Absolute Address
Data address
Program instruction address
(6) Immediate—#xx:8, #xx:16, or #xx:32: The instruction contains 8-bit (#xx:8), 16-bit (#xx:16), or 32-bit (#xx:32)
immediate data as an operand.
The ADDS, SUBS, INC, and DEC instructions contain immediate data implicitly. Some bit manipulation instructions
contain 3-bit immediate data in the instruction code, specifying a bit number. The TRAPA instruction contains 2-bit
immediate data in its instruction code, specifying a vector address.
(7) Program-Counter Relative—@(d:8, PC) or @(d:16, PC): This mode is used in the Bcc and BSR instructions. An
8-bit or 16-bit displacement contained in the instruction is sign-extended and added to the 24-bit PC contents to generate a
branch address. Only the lower 24 bits of this branch address are valid; the upper 8 bits are all assumed to be 0 (H'00). The
PC value to which the displacement is added is the address of the first byte of the next instruction, so the possible
branching range is –126 to +128 bytes (–63 to +64 words) or –32766 to +32768 bytes (–16383 to +16384 words) from the
branch instruction. The resulting value should be an even number.
(8) Memory Indirect—@@aa:8: This mode can be used by the JMP and JSR instructions. The instruction code contains
an 8-bit absolute address specifying a memory operand. This memory operand contains a branch address. The upper bits
of the absolute address are all assumed to be 0, so the address range is 0 to 255 (H'000000 to H'0000FF).
Note that the first part of the address range is also the exception vector area. For further details, refer to section 4,
Exception Handling.
If an odd address is specified in word or longword memory access, or as a branch address, the least significant bit is
regarded as 0, causing data to be accessed or instruction code to be fetched at the address preceding the specified address.
(For further information, see section 2.5.2, Memory Data Formats.)
8 bits (@aa:8)
16 bits (@aa:16)
32 bits (@aa:32)
24 bits (@aa:24)
Specified
by @aa:8
Figure 2-10 Branch Address Specification in Memory Indirect Mode
Advanced Mode
H'FFFF00 to H'FFFFFF
H'000000 to H'007FFF,
H'FF8000 to H'FFFFFF
H'000000 to H'FFFFFF
Reserved
Branch address
Advanced Mode
Rev.6.00 Oct.28.2004 page 43 of 1016
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