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| en:multiasm:papc:chapter_6_12 [2025/11/16 13:38] – [Constants] ktokarz | en:multiasm:papc:chapter_6_12 [2025/11/17 08:33] (current) – [Constants] ktokarz | ||
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| Integer numeric constants can be defined with the data assignment directives, **EQU** or the equal sign **=**. The difference is that a numeric constant defined with the EQU directive can’t be modified later in the program, while a constant created with the equal sign can be redefined many times in the program. Numeric constants can be expressed as binary, octal, decimal or hexadecimal values. They can also be a result of an expression calculated during assembly time. It is possible to use a previously defined constant in such an expression. | Integer numeric constants can be defined with the data assignment directives, **EQU** or the equal sign **=**. The difference is that a numeric constant defined with the EQU directive can’t be modified later in the program, while a constant created with the equal sign can be redefined many times in the program. Numeric constants can be expressed as binary, octal, decimal or hexadecimal values. They can also be a result of an expression calculated during assembly time. It is possible to use a previously defined constant in such an expression. | ||
| <code asm> | <code asm> | ||
| - | int_const1 EQU 5 | + | int_const1 EQU 5 ; no suffix by default decimal value |
| - | int_const_dec = 7 | + | int_const_dec = 7 ; finished with " |
| - | int_const_binary = 100100101b | + | int_const_binary = 100100101b |
| - | int_const_octal = 372o | + | int_const_octal = 372o ; finished with " |
| - | int_const_hex = 0FFA4h | + | int_const_hex = 0FFA4h |
| - | int_const_expr = const_dec | + | int_const_expr = int_const_dec |
| </ | </ | ||
| Floating-point numeric constants can be defined with the **EQU** directive only. The number can be expressed in decimal or scientific notation. | Floating-point numeric constants can be defined with the **EQU** directive only. The number can be expressed in decimal or scientific notation. | ||
| - | <code asm> | + | <code asm> |
| - | real_const1 EQU 3.1415 | + | real_const1 EQU 3.1415 |
| - | real_const2 EQU 6.28e2 | + | real_const2 EQU 6.28e2 |
| </ | </ | ||
| - | Text string constants can be defined with **EQU** or **TEXTEQU** directives. Text constants assigned with the **EQU** directive can be redefined later in the program. The **TEXEQU** is considered a text macro and is described in the section about macros. | + | Text string constants can be defined with **EQU** or **TEXTEQU** directives. Text constants assigned with the **EQU** or **TEXTEQU** directive can be redefined later in the program. The **TEXEQU** is considered a text macro and is described in the section about macros. |
| <code asm> | <code asm> | ||
| text_const1 EQU 'Hello World!' | text_const1 EQU 'Hello World!' | ||
| text_const2 EQU "Hello World!" | text_const2 EQU "Hello World!" | ||
| </ | </ | ||
| - | |||
| - | Integer constants: | ||
| - | binary, 1b, 0101B, -10y, 111111Y | ||
| - | octal, 34o, -746O, 2167q, 0Q | ||
| - | decimal, 39, 12d, 1200D, -90t, 56T | ||
| - | hex, 0h, 14A6h, 0FE3H | ||
| - | .RADIX base directive: | ||
| - | (.RADIX 16) | ||
| - | Floating point constants: | ||
| - | decimal notation, 1.0, 3.1415, -0.5 | ||
| - | exponent notation, 1e5, 1.56e-2, -15.7e+12 | ||
| - | |||
| - | String is an array of characters. | ||
| - | ‘Hello world’ | ||
| - | ”123*x=??? | ||
| - | Equal notations: | ||
| - | mov BH,’A’ | ||
| - | mov BH,”A” | ||
| - | mov BH,41h | ||