ST63140 Datasheet, PDF (59/86 Pages) STMicroelectronics – 8-BIT HCMOS MCUs FOR TV FREQUENCY & VOLTAGE SYNTHESIS WITH OSD

ST63140,142,126,156
SOFTWARE DESCRIPTION (Continued)
Instruction Set
The ST631xx Core has a set of 40 basic instruc-
tions. When these instructions are combined with
nine addressing modes, 244 usable opcodes can
be obtained. They can be divided into six different
types:load/store, arithmetic/logic, conditional
branch, control instructions, jump/call, bit manipu-
lation. The following paragraphs describe the dif-
ferent types.
All the instructions within a given type are pre-
sented in individual tables.
Load & Store. These instructions use one,two or
three bytes in relation with the addressing mode.
One operand is the Accumulator for LOAD and the
other operand is obtained from data memory using
one of the addressing modes.
For Load Immediate one operand can be any of the
256 data space bytes while the other is always
immediate data. See Table 13.
Table 13. Load & Store Instructions
Instruction
Addressing Mode
LD A, X
LD A, Y
LD A, V
LD A, W
LD X, A
LD Y, A
LD V, A
LD W, A
LD A, rr
LD rr, A
LD A, (X)
LD A, (Y)
LD (X), A
LD (Y), A
Short Direct
Short Direct
Short Direct
Short Direct
Short Direct
Short Direct
Short Direct
Short Direct
Direct
Direct
Indirect
Indirect
Indirect
Indirect
Bytes
Cycles
1
1
1
1
1
1
1
1
2
2
1
1
1
1
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Flags
Z
C
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
∆
*
LDI A, #N
LDI rr, #N
Immediate
Immediate
2
4
∆
*
3
4
*
*
Notes:
X,Y. Indirect Register Pointers, V & W Short Direct Registers
# . Immediate data (stored in ROM memory)
rr. Data space register
∆ . Affected
* . Not Affected
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