Toshiba T2N - Manual (Page 194)

3.User Data
User's manual 181
(6) Double-Length BCD
This is 8-digit BCD data which is expressed by using consecutive
registers.
10 7 10 6 10 5 10 4 10 3 10 2 10 1 10 0
Register A +1 Register A
The registers are designated in the form A +1 A , and A
becomes the lower 4 digits while A +1 becomes the upper 4
digits.
Example) When processing a double-length BCD by registers
XW001*XW000, XW000 becomes A while XW001 becomes A
+1 and XW000 becomes the lower 4 digits while XW001
becomes the upper 4 digits.
The following Table shows the numerical range and the
expression format in which double-length BCD data can be
processed.
                       
                     
Bit positions
▼
Numerical Value
Hexadecimal Expression
Register A +1’ Register A
99999999 9999 9999
∫ ∫ ∫
1 0000 0001
0 0000 0000
(MSB) (LSB)
F - - C B - - 8 7 - - 4 3 - - 0 F - - C B - - 8 7 - - 4 3 - - 0
Numerical Value
Hexadecimal Expression
Register A +1 Register A
2147483647 7FFF FFFF
∫ ∫ ∫
65536 0001 0000
65535 0000 FFFF
∫ ∫ ∫
0 0000 0000
- 1 FFFF FFFF
∫ ∫ ∫
- 65536 FFFF 0000
- 65537 FFFE FFFF
∫ ∫ ∫
- 2147483648 8000 0000