Processing Packed Decimal Data

The IBM System/360 is the outgrowth of two earlier product lines: the 704/709/7090
series and the 702/705/7080 series.

The IBM 704/709/7090 series was a line of computers designed to support scientific
research. This line supported binary arithmetic. **

The IBM 702/705/7080 series was designed to support commercial data processing.
This line supported packed decimal arithmetic.

The System/360 line was designed to bring these two lines together and implement a
single architecture. For this reason, it had to support both decimal and binary arithmetic.

** NOTE: The IBM 704 series had a 36–bit instruction word in the following format.

3 bits	15 bits	3 bits	15 bits
Prefix	Decrement	Tag	Address

LISP was developed on a 704 in 1958. Think of the following:
CAR Contents of the Address Part of the Register
CDR Contents of the Decrement Part of the Register

Packed Decimal Format

Arithmetic is done on data in one of two formats: packed decimal or binary.

Here, we discuss the packed decimal format, beginning with packed decimal constants.

A packed decimal constant is a signed integer, with between 1 and 31 digits (inclusive).
The number of digits is always odd, with a 0 being prefixed to a constant of even length.

A sign “half byte” or hexadecimal digit is appended to the representation. The common
sign–representing hexadecimal digits are as follows:

C non–negative

D negative

F non–negative, seen in the results of a PACK instruction.

If a DC (Define Constant) declarative is used to initialize storage with a packed decimal
value, one may use the length attribute. Possibly the only good use for this would be to
produce a right–adjusted value with a number of leading zeroes.

For example DC PL6’1234’ becomes

00

00

00

01

23

4C

Remember that each of these bytes holds two hexadecimal digits, not the value
indicated in decimal, so 23 is stored as 0010 0011 and 4C as 0100 1100.

Some Examples and Cautions

Here are some standard uses.

DC P‘+370’ becomes 370C

DC P‘–500’ becomes 500D

DC P‘+92’ becomes 092C

Here are some uses that, while completely logical, might best be avoided.

P1 DC PL2‘12345678’ is truncated to become 678C.
Why give a value only to remove most of it?

PCON DC PL2‘123’,‘–456’,‘789’

This creates three constants, stored as 123C, 456D, and 789C.
Only the first constant can be addressed directly.

I would prefer the following sequence, with the labels P2 and P3 being optional.

P1 DC PL2‘123’

P2 DC PL2‘–456’

P3 DC PL2‘789’

More Examples

The packed decimal format is normally considered as a fixed point format, with
a specified number of digits to the right of the decimal point.

It is important to note that decimal points are ignored when declaring a packed value.

When such are found in a constant, they are treated by the assembler as comments.

Consider the following examples and the assembly of each. Note that spaces have been
inserted between the bytes for readability only. They do not occur in the object code.

Statement Object Code Comments

P1 DC P‘1234’ 01 23 4C Standard expansion to 5 digits

P2 DC P‘12.34’ 01 23 4C The decimal is ignored.

P3 DC PL4‘-12.34’ 00 01 23 4D Negative and lengthened to 4
bytes. Leading zeroes added.

P4 DC PL5’12.34’ 00 00 01 23 4C Five bytes in length. This gives
2 bytes of leading zeroes.

P5 DC 3PL2‘0’ 00 0C 00 0C 00 0C Three values, each 2 bytes.

Packed Decimal: Moving Data

There are two instructions that might be used to move packed decimal data from
one memory location to another.

MVC S1,S2 Copy characters from location S2 to location S1

ZAP S1,S2 Copy the numeric value from location S2 to location S1.

Each of the two instructions can lead to truncation if the length of the receiving area,
S1, is less than the source memory area, S2.

If the lengths of the receiving field and the sending field are equal, either instruction
can be used and produce correct results.

The real reason for preferring the ZAP instruction for moving packed decimal data
comes when the length of the receiving field is larger than that of the sending field.

The ZAP instruction copies the contents of the sending field right to left and
then pads the receiving field with zeroes, producing a correct result.

The MVC instruction will copy extra bytes if the receiving field is longer than the
sending field. Whatever is copied is likely not to be what is desired.

Bottom line: Use the ZAP instruction to move packed decimal data, and
be sure to avoid truncation.

Packed Decimal Data: ZAP, AP, CP, and SP

We have three instructions with similar format.

ZAP S1,S2 Zero S1 and add packed S2 (This is the move discussed above)

AP S1,S2 Add packed S2 to S1

CP S1,S2 Compare S1 to S2, assuming the packed decimal format.

SP S1,S2 Subtract packed S2 from S1.

These are of the form OP D1(L1,B1),D2(L2,B2), which provide
a 4–bit number representing the length for each of the two operands.

Type	Bytes	Form	1	2	3	4	5	6
SS(2)	6	D1(L1,B1),D2(L2,B2)	OP	L1 L2	B1 D1	D1D1	B2 D2	D2D2

The first byte contains the operation code, say X‘FA’ for AP or X‘F9’ for CP.

The second byte contains two hexadecimal digits, each representing an operand length.

Each of L1 and L2 encodes one less than the length of the associated operand. This
allows 4 bits to encode the numbers 1 through 16, and disallows arguments of 0 length.

The next four bytes contain two addresses in base register/displacement format.

Packed Decimal Data: Additional Considerations

For all three instructions, the second operand must be a valid packed field terminated
with a valid sign. The usual values are ‘C’, ‘D’, and occasionally ‘F’.

For AP and SP, the first operand must be a valid packed field terminated with a valid
sign. For ZAP, the only consideration is that the destination field be large enough.

If either the sending field or the destination field (AP and SP) have just been created
by a PACK instruction, the sign half–byte may be represented by 0xF.
This is changed by the processing to 0xC or 0xD as necessary.

Some textbook hint that using ZAP to transfer a packed decimal number with 0xF as
the sign half–byte will convert that to 0xC.

Any packed decimal value with a sign half–byte of D (for negative) is considered to
sort less than any packed decimal value with a sign half–byte of C or F (positive).

Example of Packed Decimal Instructions

The form is OP D1(L1,B1),D2(L2,B2). The object code format is as follows:

Type	Bytes	Form	1	2	3	4	5	6
SS(2)	6	D1(L1,B1),D2(L2,B2)	OP	L1 L2	B1 D1	D1D1	B2 D2	D2D2

Consider the assembly language statement below, which adds AMOUNT to TOTAL.

AP TOTAL,AMOUNT

Assume: 1. TOTAL is 4 bytes long, so it can hold at most 7 digits.

2. AMOUNT is 3 bytes long, so it can hold at most 5 digits.

3. The label TOTAL is at an address specified by a displacement
of X‘50A’ from the value in register R3, used as a base register.

4. The label AMOUNT is at an address specified by a displacement
of X‘52C’ from the value in register R3, used as a base register.

The object code looks like this: FA 32 35 0A 35 2C

Example of Packed Decimal Instructions (Continued)

The form is OP D1(L1,B1),D2(L2,B2). The object code format is as follows:

Type	Bytes	Form	1	2	3	4	5	6
SS(2)	6	D1(L1,B1),D2(L2,B2)	OP	L1 L2	B1 D1	D1D1	B2 D2	D2D2

Consider FA 32 35 0A 35 2C. The operation code X‘FA’ is that for the
Add Packed (Add Decimal) instruction, which is a type SS(2). The above format applies.

The field 32 is of the form L₁ L₂.

The first value is X‘3’, or 3 decimal. The first operand is 4 bytes long.

The second value is X‘2’, or 2 decimal. The second operand is 3 bytes long.

The two–byte field 35 0A indicates that register 3 is used as the base register
for the first operand, which is at displacement X‘50A’.

The two–byte field 35 2C indicates that register 3 is used as the base register
for the second operand, which is at displacement X‘52C’.

It is quite common for both operands to use the same base register.

Condition Codes

Each of the ZAP, AP, and SP instructions will set the condition codes. As a result,
one may execute conditional branches based on these operations. The branches are:

BZ Branch Zero BNZ Branch Not Zero

BM Branch if negative BNM Branch if not negative

BP Brach if positive BNP Branch if not positive

BO Branch on overflow BNO Branch if overflow has not occurred.

An overflow will occur if the receiving field is not large enough to accept the result.

My guess is that leading zeroes are not considered in this; so that the seven digit packed
decimal number 0000123 can be moved to a field accepting four digit packed numbers.

Comparing Packed Decimal Values

The CP (Compare Packed) instruction is used to compare packed decimal values.

This sets the condition codes that can be used in a conditional branch instruction, as just
discussed. Is there any reason to compare and not then have a conditional branch?

In some sense, the CLC (Compare Character) instruction is similar and may be used
to compare packed decimal data. However, this use is dangerous, as the CLC does not
allow for many of the standards of standard algebra.

Consider the two values 123C (representing +123) and 123D (representing –123).

CP will correctly state that 123D < 123C; indeed –123 is less than +123.

CLC will state that 123D > 123C, as 12 = 12, but 3D > 3C. Remember that
these are being compared as sequences of characters without numeric values.

Consider the two values 123C (representing +123) and 123F (also representing +123).

CP will correctly state that 123C = 123F; as 123 = 123.

CLC will state that 123F > 123C, as 12 = 12, but 3F > 3C.

Consider the two values 125C (representing +123) and 12345C (representing +12345).

CP will work correctly, noting that 12345 > 00125. CLC will compare
character by character. As ‘5’ > ‘3’, it will conclude that 125 > 12345.

PACK

We now focus on conversions of decimal data between the two formats that may
be used to represent them:

1. The EBCDIC character encoding used for input and output.

2. The packed decimal format used for decimal arithmetic.

The PACK instruction can be used to convert data from zoned format into the packed
decimal format. For the moment, we shall not cover zoned decimal format.

The standard discussion of the PACK instruction focuses on positive numbers.

Consider the input data string “9876”.

Represented in EBCDIC, the string would be F9 F8 F7 F6.

One would expect this to pack to the three byte value 09 87 6C.

In fact, it packs to a variant of positive format 09 87 6F.
This value will be converted to the more standard representation when
it is first used by a packed decimal instruction.

NOTE: What about the input sequence “–123”, which is represented by the
EBCDIC string 60F1F2F3. It should pack to 123D, but it does not.
The PACK instruction is not designed to handle a leading “–”

Packing Blanks

A serious problem can arise if the field to be packed contains all blanks
(EBCDIC code 0x40).

Consider the five character input “ ” or EBCDIC 40 40 40 40 40.
This will pack to the string “000004”, which lacks a valid sign.

This invalid packed input cannot be processed by any packed decimal instruction.

Some authors suggest checking all input fields and replacing those that are blank
with all zeroes. This suggests a very common meaning of blanks as equivalent to 0.

Here is the code, directly from Abel’s textbook. The input field, RATEIN, is
supposed to contain one to five digits, but no more than five.

CLC RATEIN,=CL5‘ ’ Is this a field of five blanks

BNE D50 No, it is not all blanks

MVC RATEIN,=CL5‘00000’ Replace 5 blanks with 5 zeroes

D50 PACK RATEPK,RATEIN Store packed value in RATEPK

More on Input of Packed Data

Recall that the input of packed data is a two–step procedure.

1. Input the digits as a string of EBCDIC characters.

2. Convert the digits to packed format.

The format of the input is dictated by the appropriate data declarations.

In this example, we consider the following declaration of the form
of the input, which is best viewed as an 80–column card.

RECORDIN DS 0CL80 80 CHARACTER CARD IMAGE

DIGITS DS CL5 FIRST FIVE COLUMNS ARE INPUT

FILLER DS CL75 THE OTHER 75 ARE IGNORED

Here is a properly formatted input sequence.

1 Four blanks before the “1”.

3

13 Three blanks before the “13”.

Another Look at This Input

The important part of the data declaration for the input is as follows.

RECORDIN DS 0CL80 80 CHARACTER CARD IMAGE

DIGITS DS CL5 FIRST FIVE COLUMNS ARE INPUT

Here is the properly formatted input, viewed in columns.

Reading from right to left: Column 5 is the units column
Column 4 is the tens column
Column 3 is the hundreds column, etc.

Note that each digit is properly placed; the first line is really 00001.

One Error: Assuming Free–Formatted Input

Here is some input from the same program. It did not work.

1

3

13

17

Here is the way that the input was interpreted.

To me this looks like 10000 + 30000 + 13000 + 17000.

The Output for the Erroneous Input

I had expected the above input to give a sum of 70000. It did not.

Here is the actual output. All we get is the print echo of the first line input.

***PROGRAM FOUR CSU SPRING 2009 ***********

1

Here is the code loop for the processing routine.

B10DOIT MVC DATAPR,RECORDIN FILL THE PRINT AREA

PUT PRINTER,PRINT START THE PRINT

PACK PACKIN,DIGITSIN CONVERT INPUT TO DECIMAL

AP PACKSUM,PACKIN ADD IT UP

BR R8 RETURN FROM SUBROUTINE

What is the problem. Each of the first two lines worked.

It is either the PACK or the AP instruction that fails.

A Diagnostic

Here is the code that isolated the problem. Note the one line commented out.

B10DOIT MVC DATAPR,RECORDIN FILL THE PRINT AREA

PUT PRINTER,PRINT START THE PRINT

PACK PACKIN,DIGITSIN CONVERT INPUT TO DECIMAL

*** AP PACKSUM,PACKIN ADD IT UP

BR R8 RETURN FROM SUBROUTINE

Here is the output for the code fragment above.

************** TOP OF DATA *****************************

***PROGRAM FOUR CSU SPRING 2009 ***********

1

3

13

17

THE SUM = 000000

************ BOTTOM OF DATA ****************************

The Diagnosis

Look again at the input.

The first line, as EBCDIC characters is read as follows.

F1 40 40 40 40

The PACK command processes right to left. It will process any kind of data,
even data that do not make sense as digits.

The above will pack to something like X‘10004’, an invalid packed format.

With no valid sign indicator, the AP instruction will fail.

Printing Packed Data

In order to print packed decimal data, it must be converted back to a string
of EBCDIC characters.

The unpack command, UNPK, appears to convert data in Packed Decimal
format to EBCDIC format, actually converts to Zoned Decimal format.

UNPK almost converts to EBCDIC. It has an unfortunate side effect, due to the
simplicity of its implementation, which is a direct conversion to Zoned format.

The problem occurs when handling the sign code, “C” or “D” in the Packed
Decimal format. This occurs in the rightmost byte of a packed decimal value.

Consider the decimal number 47, represented in binary in register R4.

CVD R4,PACKOUT produces the packed decimal 047C. This is correct.

When this is unpacked it should become F0 F4 F7

Unpack just swaps the sign half byte: F0 F4 C7.

This prints as 04G, because 0xC7 is the EBCDIC code for the letter ‘G’.

We have to correct the zone part of the last byte.

Printing Packed Data (Part 2)

Here is the code that works for five digit numbers. It is written as a
subroutine, that is called as BALR R8,NUMOUT.

NUMOUT CP QTYPACK, =P‘0’

BNM NOTNEG

MVI QTYOUT+5,C‘-’ PLACE SIGN AT QTYOUT+5

NOTNEG UNPK QTYOUT,QTYPACK PRODUCE FORMATTED NUMBER

MVZ QTYOUT+4(1),=X’F0’ MOVE 1 BYTE

* TO ADDRESS QTYOUT+4

BR 8 RETURN ADDRESS IN REGISTER 8

QTYPACK DS PL3 HOLDS FIVE DIGITS IN THREE BYTES

QTYOUT DS 0CL6

DIGITS DS CL5 THE FIVE DIGITS

DC CL1’ ’ THE SIGN

Again, the expression QTYOUT+4 is an address, not a value.

If QTYOUT holds C‘01234’, then QTYOUT+4 holds C ‘4’.

Unpacking and Editing Packed Decimal Data

Each of the UNPK (Unpack) and the ED (Edit) instruction will convert packed
decimal data into a form suitable for printing.

The ED instruction seems to be the more useful. In addition to producing the
correct print representation of all digits, it allows for the standard output formats.

The use of the ED instruction is a two–step process.

1. Define an edit pattern to represent the punctuation, sign, and handling of
leading zeroes that is required. Use the MVC instruction to move
this into the output position.

2. Use the ED instruction to overwrite the output position ** with the output
string that will be formatted as specified by the edit pattern.

Here is an example. Note that there are a number of length constraints, specifically
that the length of the edit pattern match the length of the output area.

** NOTE: The first character in the edit pattern is a fill character.
It is not overwritten.

ED Instruction: A Simple Example

Here is the book’s example

MVC COUNPR,=X‘40202020’ Four bytes of pattern

ED COUNPR,COUNT

More code here

COUNT DC PL‘001’

COUNPR DS CL4

Note the sequence of events in these two lines of code.

1. The edit pattern is moved into the output field. The leading pair of hexadecimal
digits, 0x40, state that a blank,‘ ’, will replace all leading zeroes.

2. The decimal value is edited into the output field COUNPR, overwriting
the edit pattern.

The result is printed as the four character sequence “ 1”, represented in EBCDC
code as 0x404040F1.

ED: Basic Rules

The basic form of the instruction is ED S1,S2

The first operand, S1, references the leftmost byte of the edit word, which
has been placed in the output area.

The second operand, S2, references a packed field to be edited.

One key concept in the editing for output is called “significance”. In many uses,
leading zeroes are not treated as significant and are replaced by the fill character.

Thus, the number 001 would print as “1”.

There are times in which one wants one or more leading zeroes to be printed. As an
example, consider the real number 0.25, which is stored as 025C. It might best be
printed as “0.25” with at least one leading zero. This leads to the concept called
“forcing significance”, in which leading zeroes are printed.

The Fill Character

The leftmost hexadecimal byte in the output area before the execution of the
instruction begins represents the fill character to use when replacing non–significant
leading zeroes. Two standard values are:

0x40 a blank ‘ ’

0x5C an asterisk ‘*’ Often used in check printing.

Consider the three digit number 172, stored internally as 172C. For now, assume that
the field from which it will be printed allows for five digits.

With a fill character of 0x40 (blank), this would normally be printed as 172.

We force significance to cause either 0172 or 00172 to be printed. For this number,
with a fill character of 0x40, our options would be one of the three following.

172
0172
00172

With a fill character of 0x5C, we might have one of the three following.

**172
*0172
00172

The Edit Word: Encountering Significance

Here are some of the commonly used edit characters. Note that it is more convenient
to represent these by their hexadecimal EBCDIC.

One key idea is the encounter of significance. The instruction generates digits for
possible printing from left (most significant) to right (least significant). Two events
cause this encounter: 1) a non–zero digit is generated, and 2) a digit is encountered
that is associated with the 0x21 edit pattern.

As noted above, the first character is the fill character. The other codes are

0x20 Digit selector. This represents a digit to be printed, unless it
happens to be a leading non–significant zero.
In that case, the fill character is printed.

0x21 Digit selector and significance starter. This not only represents a
digit to be printed, but it also forces significance. Each digit
to the right will be printed, even if a leading zero.

Note: Unless one is careful, ED might result in an output field that is all blanks.

For printing integer values, one might seriously consider ending the edit pattern (word)
with the values 0x2120. Significance is forced after the next–to–last digit, forcing at
least one digit to be printed.

The Edit Word: Formatting the Output

Part of the function of the ED command is to allow standard formatting of the output,
including decimal points and commas. Handling of negative numbers is a bit strange.

Here are the standard formatting patterns.

0x4B The decimal point. If significance has been encountered, the decimal
point is printed. Otherwise, the fill character is printed.

0x6B The comma. If significance has been encountered, the comma is
printed. Otherwise, the fill character is printed.

0x60 The minus sign, “–”. This is used in an unexpected way.

The standard for use of the minus sign arises from conventions found in commercial
use. The minus sign is placed at the end of the number.

Thus the three digit positive number 172 would be printed as 172
and the three digit negative number –172 would be printed as 172–.

The edit pattern for this output (ignoring the significance issue) would be as follows:

0x4020202060. The fill character is a blank. There are three digits followed by
a sign field, which is printed as either “–” or the fill character.

ED: An Example with Formatting

In this example, it is desired to print a seven digit number, formatted as follows.

1. It is a fixed point number, with two digits to the right of the decimal.

2. It has five digits to the left of the decimal and places a comma in the
standard location if significance has been encountered.

3. It will be printed with a terminating “–” if the number is negative.

This situation is illustrated in the following graphic.

The edit pattern for this example would be as follows:

	1	2		3	4	5		6	7
40	20	20	6B	20	21	20	4B	20	20	60

Note: The significance forcer at digit 4 will insure that digit 5 is printed,
even if it is a zero.

ED: Why the “*” Fill Character

One option for the fill character is 0x5C, the asterisk. Why is this used?

Consider the above seven–digit example, in which the number is to be viewed
as a money amount. We shall use the dollar sign, “$”, in the amount.

Consider the amount $123.45. We would like to print it in this fashion,
but placing the dollar sign in this way presents difficulties.

Standard coding practice would have been to place the dollar sign in a column
just prior to that for the digits. The format would have been as follows.

Column	0	1	2	3	4	5	6	7	8	9	10
	$	Digits		,	Digits			.	Digits		–

If the blank fill character were chosen, this would print as $ 123.45.
Note the spaces before the first digit. To prevent fraud, we print $***123.45

ED: A More Complete Example

We now show the complete code for producing a printable output from the
seven digit packed number considered above. We shall use “*” as a fill character.

Note that the output will be eleven EBCDIC characters.

Here is the code.

PRINTAMT MVC AMNTPR,EDITWD

ED AMTPR,AMTPACK

*

EDITWD DC X‘5C20206B2021204B202060’

*

AMTPACK DS PL4 FOUR BYTES TO STORE SEVEN DIGITS.
*

AMTOUT DS 0CL12 TWELVE EBCDIC CHARACTERS

DOLLAR DC C‘$’ THE DOLLAR SIGN

AMTPR DS CL11 THE FORMATTED PRINT OUTPUT

ED: Another Example Using an Edit Pattern

This example is adapted from the textbook. Suppose that we have the following.

The packed value to be printed is represented by
DC PL3‘7’ This is represented as 00 00 7C.

The edit pattern, when placed in the output area beginning at byte address 90,
is as shown below.

Address	90	91	92	93	94	95	96	97
Code	40	20	21	20	4B	20	20	60

Note the structure here: 3 digits to the left of the decimal (at least one will be printed),

the decimal point, and

two digits to the right of the decimal.

This might lead one to expect something like “000.07” to be printed.

We now follow the discussion on pages 181 and 182 of the textbook and note a
discrepancy in the books description. We shall see what to make of this.

ED: First Two Digits

At address 90 the contents are 0x40, assumed to be the fill character.
This location is not altered.

Address	90	91	92	93	94	95	96	97
Code	40	20	21	20	4B	20	20	60

At address 91 the contents 0x20 is a digit selector. The first digit
of the packed amount is examined. It is a 0. 00007C
ED replaces the 0x20 with the fill character, 0x40.

Address	90	91	92	93	94	95	96	97
Code	40	40	21	20	4B	20	20	60

At address 92 the contents 0x21 is a digit selector and a significance forcer
for what follows. The second digit 00007C
of the packed amount is of the packed amount is examined.
It is a 0. ED replaces the 0x21 with the fill character, 0x40.

Address	90	91	92	93	94	95	96	97
Code	40	40	40	20	4B	20	20	60

ED: Next Two Digits

At address 93 the contents 0x20 is a digit selector. Significance has been
encountered. The third digit of the packed 00007C
amount is of the packed amount is examined.
It is a 0. ED replaces the 0x20 with 0xF0, the code for ‘0’.

Address	90	91	92	93	94	95	96	97
Code	40	40	40	F0	4B	20	20	60

At address 94 the contents 0x4B indicate that a decimal point is to be printed
if significance has been encountered. It has been, so the pattern
is not changed. Had significance not been encountered, this
would have been replaced by the fill character.

Address	90	91	92	93	94	95	96	97
Code	40	40	40	F0	4B	20	20	60

At address 95 the contents 0x20 is a digit selector. Significance has been
encountered. The fourth digit of the packed 00007C
amount is of the packed amount is examined.
It is a 0. ED replaces the 0x20 with 0xF0, the code for ‘0’.

Address	90	91	92	93	94	95	96	97
Code	40	40	40	F0	4B	F0	20	60

ED: Last Digit

At address 96 the contents 0x20 is a digit selector. Significance has been
encountered. The fourth digit of the packed 00007C
amount is of the packed amount is examined.
It is a 7. ED replaces the 0x20 with 0xF7, the code for ‘7’.

Address	90	91	92	93	94	95	96	97
Code	40	40	40	F0	4B	F0	F7	60

At address 97 the contents 0x60 indicate to place a minus sign if the number
to be printed is found to be negative. It is not, so the instruction
replaces the negative sign with the fill character.

Address	90	91	92	93	94	95	96	97
Code	40	40	40	F0	4B	F0	F7	40

At this point, the process terminates. We have the EBCDIC representation of
the string to be printed. As characters, this would be “ 0.07 ”.

Note that additional code would be required to print something like “ $ 0.07 ”.
This would involve a scan of the output of the ED instruction and placing the dollar
sign at a place deemed appropriate.