Subfield 3: Type Extension

The syntax for coding the type extension is shown in the subfield format on page ***.

You may omit the type extension subfield. If specified, the assembler, using this field in conjunction with the type subfield, determines how to interpret the constant and translate it into the correct format. The type extension is specified by a single-letter code as shown in Table 20.

Table 20. Type extension codes for constants
Type Type Extension Description
C A ASCII character constant
E EBCDIC character constant
U Unicode UTF-16 character constant
E H Hexadecimal floating-point constant
B Binary floating-point constant
D Decimal floating-point constant
D H Hexadecimal floating-point constant
B Binary floating-point constant
D Decimal floating-point constant
L H Hexadecimal floating-point constant
B Binary floating-point constant
D Decimal floating-point constant
Q Hexadecimal floating-point, quadword alignment
F D Doubleword fixed-point constant
A D Doubleword address constant
V D Doubleword address constant
J D Doubleword address constant
Q D Doubleword address constant
Q Y 20-bit address constant
R D Doubleword address constant
S Y 20-bit address constant

The type extension specification, in conjunction with the type subfield, indicates to the assembler:

  1. How to assemble the nominal value(s) specified in subfield 6; that is, which binary representation or machine format the object code of the constant must have.
  2. At what boundary the assembler aligns the constant, if no length modifier is present.
  3. How much storage the constant occupies, according to the implicit length of the constant, if no explicit length modifier is present (for details, see Padding and truncation of values).

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