647
Floating-point Math Instructions Section 3-15
Storage of ASCII Text The following diagrams show how the ASCII text number is converted to float-
ing-point data. Different conversion methods are used for numbers stored with
decimal notation and scientific notation.
2D 20
20 31
2E 32
33 34
45 2B
30 32
00 00
−
SP SP 1 . 2 3 4 E + 0 2
(2D)(20)(20)(31)(2E)(32)(33)(34)(45)(2D)(31)(38)
15 87 0
−1.234×10
2
1100110011001101
1100001011110110
D
D+1
1100110011001101
1100001011110110
15 0
Scientific notation
Exponent
Spaces are
ignored during
conversion
Sign
32-bit floating-point data
Conversion of ASCII text number
to 32-bit floating-point data
Stored in D and D+1.
00
S
ASCII Character Storage
Up to 00 hex
(25 characters max.)
FVAL(449) converts the ASCII characters
starting with the leftmost byte of S and
continuing until a byte containing 00 hex is
reached. There must be a byte containing
00 hex within the first 25 bytes.
15 078
00
SP SP
(20)
(20)
00
Decimal notation
Digit
25 characters max.
The 7th and higher digits are ignored.
(The sign, decimal point, and exponent
characters are not counted as digits.)
Any spaces (20 hex) or zeroes (30 hex)
before the first digit are ignored.
Positive number: Space (20 hex) or Plus sign (2B hex)
Negative number: Minus sign (2D hex)
Integer part
Sign
Fractional part
Decimal
point
Sign
15 078
(20)
00
SP
E
(20)
. (2E)
E (45)
00
Scientific notation
25 characters max.
The 7th and higher digits are ignored.
(The sign, decimal point, and exponent
characters are not counted as digits.)
Any spaces (20 hex) or zeroes (30 hex)
before the first digit are ignored.
Positive number: Space (20 hex) or Plus sign (2B hex)
Negative number: Minus sign (2D hex)
Positive: + (2B hex)
Negative: - (2D hex)
Exponential part
Sign
Fractional part
Decimal
point
Integer part
Sign
E (45)
Sign
Digit
Digit
Digit
Sign
Digit Digit
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