====== MAME Debugger Expressions ======

Expressions can be used anywhere a numeric parameter is expected. The syntax for expressions is very close to standard C-style syntax with full operator ordering and parentheses. There are a few operators missing (notably the trinary ''? :'' operator), and a few new ones (memory accessors). The table below lists all the operators in their order, highest precedence operators first.

^ Operator                    ^ Description           ^
| ( )                         | standard parentheses  |
| ++ --                       | postfix increment/decrement  |
| ++ -- ~ ! - + b@ w@ d@ q@   | prefix inc/dec, binary NOT, logical NOT, unary +/-, memory access  |
| * / %                       | multiply, divide, modulus  |
| + -                         | add, subtract         |
| %%<< >>%%                   | shift left/right      |
| < %%<=%% > %%>=%%           | less than, less than or equal, greater than, greater than or equal  |
| == !=                       | equal, not equal      |
| &                           | binary AND            |
| %%^%%                       | binary XOR            |
| %%|%%                       | binary OR             |
| &&                          | logical AND           |
| %%||%%                      | logical OR            |
| = *= /= %= += -= <<= >>= &= %%|=%% %%^=%%  | assignment  |
| ,                           | separate terms, function parameters  |

These are the differences from C behaviors. First, All math is performed on full 64-bit unsigned values, so things like ''a < 0'' won't work as expected. Second, the logical operators ''&&'' and ''||'' do not have short-circuit properties -- both halves are always evaluated. Finally, the new memory operators work like this: ''b@<addr>'' refers to the byte read from ''<addr>''. Similarly, ''w@'' refers to a word in memory, ''d@'' refers to a dword in memory, and ''q@'' refers to a qword in memory. The memory operators can be used as both lvalues and rvalues, so you can write ''b@100 = ff'' to store a byte in memory. By default these operators read from the program memory space, but you can override that by prefixing them with a ''d'' or an ''i''. So ''dw@300'' refers to data memory word at address ''300'' and ''id@400'' refers to an I/O memory dword at address ''400''.