HD404339 Datasheet, PDF (15/80 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer with large-capacity memory

Registers and Flags
HD404339 Series
Accumulator
Initial value: Undefined, R/W
3
0
(A)
B register
W register
Initial value: Undefined, R/W
Initial value: Undefined, R/W
3
0
(B)
10
(W)
X register
Y register
Initial value: Undefined, R/W
Initial value: Undefined, R/W
3
0
(X)
3
0
(Y)
SPX register
Initial value: Undefined, R/W
SPY register
Initial value: Undefined, R/W
Carry
Initial value: Undefined, R/W
Status
Initial value: 1, no R/W
Program counter
13
Initial value: 0,
no R/W
Stack pointer
Initial value: $3FF, no R/W
(PC)
9
5
1 11 1
3
0
(SPX)
3
0
(SPY)
0
(CA)
0
(ST)
0
0
(SP)
Figure 6 Registers and Flags
13