Delta Tau GEO BRICK LV User Manual
Turbo PMAC User Manual
Turbo PMAC Computational Features
241
The internal format of 48-bit floating-point registers is shown in the following table:
X-word:
Bit: 23 22 21 20 19 18 17 16 15 14 13 12
Part: Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant
Val: -2
Part: Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant
Val: -2
0
+2
-1
+2
-2
+2
-3
+2
-4
+2
-5
+2
-6
+2
-7
+2
-8
+2
-9
+2
-10
+2
-11
Bit:
11 10 9 8 7 6 5 4 3 2 1 0
Part: Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant
Val: +2
Val: +2
-12
+2
-13
+2
-14
+2
-15
+2
-16
+2
-17
+2
-18
+2
-19
+2
-20
+2
-21
+2
-22
+2
-23
Y-word:
Bit: 23 22 21 20 19 18 17 16 15 14 13 12
Part: Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant
Val: +2
Part: Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant Mant
Val: +2
-24
+2
-25
+2
-26
+2
-27
+2
-28
+2
-29
+2
-30
+2
-31
+2
-32
+2
-33
+2
-34
+2
-35
Bit:
11 10 9 8 7 6 5 4 3 2 1 0
Part: Exp Exp Exp Exp Exp Exp Exp Exp Exp Exp Exp Exp
Val: +2
Val: +2
11
+2
10
+2
9
+2
8
+27
1
+2
6
+2
5
+2
4
+2
3
+2
2
+2
1
+2
0
Mant:
Mantissa – The mantissa of a floating-point number in standard format. The
mantissa should have the range 0.5 <= Mant < 1.0, or –1.0 <= Mant < -0.5. Mant
= 0.0 when number is exactly 0.
mantissa should have the range 0.5 <= Mant < 1.0, or –1.0 <= Mant < -0.5. Mant
= 0.0 when number is exactly 0.
Exp:
Exponent – The exponent of a floating-point number in modified format. The 12-
bit value here (0 <= Exp <= 4095) should have a value of 2047 subtracted from it
(n = Exp -2047; -2048 <= n <= +2047); then 2 is raised to the power n, and the
resulting value is multiplied by the mantissa. Exp = 0 when number is exactly 0.
bit value here (0 <= Exp <= 4095) should have a value of 2047 subtracted from it
(n = Exp -2047; -2048 <= n <= +2047); then 2 is raised to the power n, and the
resulting value is multiplied by the mantissa. Exp = 0 when number is exactly 0.
Receiving Values
Constant values sent from the host as part of command lines are sent as ASCII text, either as decimal
values or hexadecimal values. Hexadecimal values must be preceded by a $ character; they must be
unsigned, and they cannot include fractional values. Decimal values can be positive or negative, and can
include fractional values. The Turbo PMAC value interpreter does not support exponential notation, and
it is limited to passing through values in the range +2
values or hexadecimal values. Hexadecimal values must be preceded by a $ character; they must be
unsigned, and they cannot include fractional values. Decimal values can be positive or negative, and can
include fractional values. The Turbo PMAC value interpreter does not support exponential notation, and
it is limited to passing through values in the range +2
+35
, or +3.43 x 10
+10
. Values outside this range are
truncated to the maximum or minimum values of the range.
Examples:
1234
3
03 (leading zeros OK)
-27.656
0.001
.001 (leading zero not required)
$ff00 (interpreted as hexadecimal)
Reporting Values
Turbo PMAC reports numerical values to the host computer as part of response lines in decimal ASCII
text form (although address values can be reported in hexadecimal ASCII form if I9 = 2 or 3 – see below).
The value reporter is limited to passing values in the range of +2
text form (although address values can be reported in hexadecimal ASCII form if I9 = 2 or 3 – see below).
The value reporter is limited to passing values in the range of +2
+47
, or +1.41 x 10
+14
. Values outside of
this range are truncated to the maximum or minimum values of the range.