Instruction Reference Manual
87
Description
•
LDD:
Loads the memory location whose address is in DE with the data at the address in HL.
Then it decrements the data in BC, DE, and HL.
•
LDDR:
While the data in BC does not equal 0 then the memory location whose address is in DE
is loaded with the data at the address in HL. Then it decrements the data in BC, DE, and HL. The
instruction then repeats until BC equals zero.
•
LDI:
Loads the memory location whose address is in DE with the data at the address in HL.
Then the data in BC is decremented and the data in DE and HL is incremented.
•
LDIR:
While the data in BC does not equal 0 then the memory location whose address is in DE
is loaded with the data at the address in HL. Then the data in BC is decremented and the data in
DE and HL are incremented. The instruction then repeats until BC equals zero.
If any of these block move instructions are prefixed by IOI or IOE, the destination will be in the specified I/O
space. Add 1 clock for each iteration for the prefix if the prefix is IOI (internal I/O). If the prefix is IOE, add 2
clocks plus the number of I/O wait states enabled. The V flag is cleared when BC transitions from 1 to 0. If
the V flag is not cleared another step is performed for the repeating versions of the instructions. Interrupts can
occur between different repeats, but not within an iteration equivalent to LDD or LDI. Return from the inter-
rupt is to the first byte of the instruction which is the I/O prefix byte if there is one
.
LDD
LDDR
LDI
LDIR
Opcode
Instruction
Clocks
Operation
ED A8
LDD
10 (2,2,1,2,3)
(DE) = (HL); BC = BC - 1;
DE = DE - 1; HL = HL - 1
ED B8
LDDR
6 + 7i (2,2,1,(2,3,2)i,1)
repeat:
(DE) = (HL); BC = BC - 1;
DE = DE - 1; HL = HL - 1
until { BC == 0 }
ED A0
LDI
10 (2,2,1,2,3)
(DE) = (HL); BC = BC - 1;
DE = DE + 1; HL = HL + 1
ED B0
LDIR
6 + 7i (2,2,1,(2,3,2)i,1)
repeat:
(DE) = (HL); BC = BC - 1;
DE = DE + 1; HL = HL + 1
until { BC == 0 }
Flags
ALTD
I/O
S
Z
L/V
C
F
R
SP
S
D
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Summary of Contents for 2000
Page 2: ...ii Rabbit 2000 3000 Microprocessor...
Page 4: ...iv Rabbit 2000 Microprocessor...
Page 16: ...12 Rabbit 2000 3000 Microprocessor...
Page 164: ...160 Instruction Reference Manual...
