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ld.a %rd, [%rb]
Function
32-bit data transfer
Standard)
Extension 1) rd(23:0) ← A[rb + imm13](23:0), ignored ← A[rb + imm13](31:24)
Extension 2) rd(23:0) ← A[rb + imm24](23:0), ignored ← A[rb + imm24](31:24)
15 14 13 12 11 10
Code
0
0
1
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IL
IE
C
Flag
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–
–
–
Mode
Src: Register indirect %rb = %r0 to %r7
Dst: Register direct %rd = %r0 to %r7
CLK
One cycle (two cycles when the ext instruction is used)
Description
(1) Standard
ld.a
The 32-bit data (the eight high-order bits are ignored) in the specified memory location is
transferred to the rd register. The rb register contains the memory address to be accessed.
(2) Extension 1
ext
ld.a
The e x t instruction changes the addressing mode to register indirect addressing with
displacement. As a result, the content of the rb register with the 13-bit immediate imm13 added
comprises the memory address, the 32-bit data (the eight high-order bits are ignored) in which
is transferred to the rd register. The content of the rb register is not altered.
(3) Extension 2
ext
ext
ld.a
The addressing mode changes to register indirect addressing with displacement, so the content
of the rb register with the 24-bit immediate imm24 added comprises the memory address, the
32-bit data (the eight high-order bits are ignored) in which is transferred to the rd register. The
content of the rb register is not altered.
(4) 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 displacement 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.
S1C17 CORE MANUAL
(Rev. 1.2)
rd(23:0) ← A[rb](23:0), ignored ← A[rb](31:24)
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8
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0
0
0
r d
0
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V
Z
N
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–
–
–
%rd,[%rb]
; memory address = rb
imm13
%rd,[%rb]
; memory address = rb + imm13
imm11
; imm11(10:0) = imm24(23:13)
imm13
; = imm24(12:0)
%rd,[%rb]
; memory address = rb + imm24
Seiko Epson Corporation
5
4
3
2
1
0
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0
1
1
r b
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7 DETAILS OF INSTRUCTIONS
7-67
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