The numeric argument of a TECO command may consist of:
- A single integer
- One of TECO's numeric variables
- The numeric contents of a Q-register
- An arithmetic expression combining these elements
TECO-64 provides all of the standard arithmetic operators as classic TECO, but additionally provides a set of extended operators, as described in the following two sections.
| Command | Example | Function |
|---|---|---|
| + | +2=2 | Unary plus. |
| + | 5+6=11 | Binary addition. |
| - | -2=-2 | Unary minus (2's complement negation). |
| - | 8-2=6 | Binary subtraction. |
| * | 8*2=16 | Binary multiplication. |
| / | 8/3=2 | Binary division yielding quotient. |
| & | 12&10=8 | Bitwise logical AND. |
| # | 12#10=14 | Bitwise logical OR. |
| ^_ | 5^_=-6 | Unary 1's complement. Note that it is used after an expression. |
| ( ) | 3*(42/16)=6 | Expression grouping. |
If the E1&1 flag bit is set, then there are additional operators that can be used, as long as they are within parentheses (to avoid confusion with commands that may use the same characters). Note that any of the multi-character operators must be entered as a single token, with no intervening whitespace.
Also, TECO-64 uses a value of 0 for true and -1 for false, as shown in the examples for relational and logical NOT operators. This is in keeping with classic TECO, which considered a numeric value as true if it had all bits set, and false if it had no bits set. This is why colon-modified commands return values of either 0 or -1.
| Command | Example | Function |
|---|---|---|
| == | (1==1)=-1 | Relational comparison for equality. |
| <> | (1<>1)=0 | Relational comparison for inequality. |
| < | (1<1)=0 | Relational comparison for less than. |
| <= | (1<=1)=-1 | Relational comparison for less than or equal. |
| > | (1>1)=0 | Relational comparison for greater than. |
| >= | (1>=1)=0 | Relational comparison for greater than or equal. |
| // | (7//3)=1 | Binary division yielding remainder. |
| ! | (!0)=-1 | Bitwise logical NOT. |
| ~ | (7~3)=4 | Bitwise logical XOR. |
| << | (1<<3)=8 | Arithmetic left shift. |
| >> | (16>>2)=4 | Arithmetic right shift. |
In TECO-64, arithmetic expressions may evaluated in one of two ways. If the E1&2048 flag bit is clear, expressions are evaluated from left to right without any operator precedence, as they are in classic TECO. However, if the E1&2048 flag bit is set, operators have the same precedence and associativity in C, as described in the following table, which lists operators from highest to lowest precedence.
| Operator | Precedence | Associativity | Function |
|---|---|---|---|
| ( ) | 1 | Left | Expression grouping. |
| ! | 2 | Right | Bitwise logical NOT. |
| ^_ | 2 | Left | Unary 1's complement. |
| - | 2 | Right | Unary minus (2's complement negation). |
| + | 2 | Right | Unary plus. |
| * | 3 | Left | Binary multiplication. |
| / | 3 | Left | Binary division yielding quotient. |
| // | 3 | Left | Binary division yielding remainder. |
| + | 4 | Left | Binary addition. |
| - | 4 | Left | Binary subtraction. |
| << | 5 | Left | Arithmetic left shift. |
| >> | 5 | Left | Arithmetic right shift. |
| < | 6 | Left | Relational comparison for less than. |
| <= | 6 | Left | Relational comparison for less than or equal. |
| > | 6 | Left | Relational comparison for greater than. |
| >= | 6 | Left | Relational comparison for greater than or equal. |
| == | 7 | Left | Relational comparison for equality. |
| <> | 7 | Left | Relational comparison for inequality. |
| & | 8 | Left | Bitwise logical AND. |
| ~ | 9 | Left | Bitwise logical XOR. |
| # | 10 | Left | Bitwise logical OR. |
Parentheses may be used to override the normal order of evaluation of an expression. If parentheses are used, all operations within the parentheses are performed, before operations outside the parentheses, according to the precedence and associativity rules in effect at that point. Parentheses may be nested, in which case the innermost expression contained by parentheses will be evaluated first.