Rabbit 2000, Instruction & Reference Manual

Page: 99 / 174

Rabbit 3000A Instruction
Instruction Reference Manual 95
Description
•
LSDR
: While the data in BC does not equal 0, the memory location whose address is in DE is
loaded with the data at the address in HL. The data in BC, DE, and HL is then decremented.
This instruction then repeats until BC equals zero. If this instruction is prefixed by IOI or IOE,
the source will be in the specified I/O space.
•
LSIR
: While the data in BC does not equal 0, the memory location whose address is in DE is
loaded with the data at the address in HL. The data in BC is then decremented, and the data in
DE and HL is incremented. This instruction then repeats until BC equals zero. If this instruction
is prefixed by IOI or IOE, the source will be in the specified I/O space.
•
LSDDR
: While the data in BC does not equal 0, the memory location whose address is in DE is
loaded with the data at the address in HL. The data in BC and DE (but not HL) is then decre-
mented. This instruction then repeats until BC equals zero. If this instruction is prefixed by IOI
or IOE, the source will be in the specified I/O space.
• LSIDR : While the data in BC does not equal 0, the memory location whose address is in DE is
loaded with the data ta the address in HL. The data in BC is then decremented and DE incre-
mented (the data in HL remains unchanged). This instruction then repeats until BC equals zero.
If this instruction is prefixed by IOI or IOE, the source 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. Return from the interrupt is to the first byte of the
instruction which is the I/O prefix byte if there is one. These instructions are implemented for the Rabbit
3000A.
LSDR
LSIR
LSDDR
LSIDR
Opcode Instruction Clocks Operation
ED F8 LSDR 6+7i
(2,2,1,(2,3,2)i,1)
(DE) = (HL); BC = BC-1;
DE = DE-1; HL = HL-1;
repeat while BC != 0
ED F0 LSIR 6+7i
(2,2,1,(2,3,2)i,1)
(DE) = (HL); BC = BC-1;
DE = DE+1; HL = HL+1;
repeat while BC != 0
ED D8 LSDDR 6+7i
(2,2,1,(2,3,2)i,1)
(DE) = (HL);
BC = BC-1; DE = DE-1;
repeat while BC != 0
ED D0 LSIDR 6+7i
(2,2,1,(2,3,2)i,1)
(DE) = (HL);
BC = BC-1; DE = DE+1;
repeat while BC != 0
Flags ALTD I/O
S Z L/V C F R SP S D
- - • - •