Epson S1C17 Series Manual page 139

7 DETAILS OF INSTRUCTIONS
(2) Standard (example of post-increment option)
ld.a
The content of the rs register (24-bit data) is transferred to the specified memory location. The
rb register contains the memory address to be accessed. This instruction writes 32-bit data with
the eight high-order bits set to 0 in the memory. The memory address will be incremented by
two bytes after the data transfer has finished.
(3) Extension 1 (example of post-decrement option)
ext
ld.a
The content of the rs register (24-bit data) is transferred to the specified memory location. The
rb register contains the memory address to be accessed. This instruction writes 32-bit data with
the eight high-order bits set to 0 in the memory. The memory address will be decremented by
imm13 bytes after the data transfer has finished.
(4) Extension 2 (example of pre-decrement option)
ext
ext
ld.a
After the memory address specified by the rb register is decremented by imm24 bytes, the
content of the rs register (24-bit data) is transferred to the decremented address. This instruction
writes 32-bit data with the eight high-order bits set to 0 in the memory.
(5) Delayed slot instruction
This instruction may be executed as a delayed slot instruction by writing it directly after
a branch instruction with the "d" bit. In this case, extension of the immediate by the ext
instruction cannot be performed.
Caution
The rb register and the immediate value must specify a 32-bit boundary address (two least
significant bits = 0). Specifying other address causes an address misaligned interrupt. Note,
however, that the data transfer is performed by setting the two least significant bits of the address to 0.
7-80
[%rb]+,%rs ; Destination memory address = rb
; post increment: rb + 4
imm13
[%rb]-,%rs ; Destination memory address = rb
; post decrement: rb - imm13
imm11 ; imm11(10:0) = imm24(23:13)
imm13 ; = imm24(12:0)
-[%rb],%rs ; Destination memory address = rb - imm24
Seiko Epson Corporation
S1C17 CORE MANUAL
(REV. 1.2)