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S1C17 CORE MANUAL
Seiko Epson Corporation
7-73
(Rev. 1.2)
ld.a %rd, [%sp + imm7]
Function
32-bit data transfer
Standard)
rd
(23:0)
←
A[sp +
imm7
](23:0), ignored
←
A[sp +
imm7
](31:24)
Extension 1)
rd
(23:0)
←
A[sp +
imm20
](23:0), ignored
←
A[sp +
imm20
](31:24)
Extension 2)
rd
(23:0)
←
A[sp +
imm24
](23:0), ignored
←
A[sp +
imm24
](31:24)
Code
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 0 1 1
r d
imm7
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Flag
IL IE C V Z N
– – – – – –
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Mode
Src: Register indirect with displacement
Dst: Register direct
%rd
=
%r0
to
%r7
CLK
Two cycles
Description
(1) Standard
ld.a %rd,[%sp + imm7]
; memory address = sp + imm7
The 32-bit data (the eight high-order bits are ignored) in the specified memory location is
transferred to the
rd
register. The content of the current SP with the 7-bit immediate
imm7
added as displacement comprises the memory address to be accessed.
(2) Extension 1
ext imm13
;
=
imm20(19:7)
ld.a %rd,[%sp + imm7]
; memory address = sp + imm20,
;
imm7 = imm20(6:0)
The
ext
instruction extends the displacement to a 20-bit quantity. As a result, the content of the
SP with the 20-bit immediate
imm20
added comprises the memory address, the 32-bit data (the
eight high-order bits are ignored) in which is transferred to the
rd
register.
(3) Extension 2
ext imm4
;
imm4(3:0) = imm24(23:20)
ext imm13
;
=
imm24(19:7)
ld.a %rd,[%sp + imm7]
; memory address = sp + imm24,
;
imm7 = imm24(6:0)
The two
ext
instructions extend the displacement to a 24-bit quantity. As a result, the content
of the SP 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.
(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.
Example
ext 0x1
ld.a %r0,[%sp + 0x4] ; r0
←
[sp + 0x84]
Caution
The SP 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.