diff options
Diffstat (limited to 'docs/source/debugger/expressions.rst')
-rw-r--r-- | docs/source/debugger/expressions.rst | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/docs/source/debugger/expressions.rst b/docs/source/debugger/expressions.rst new file mode 100644 index 00000000000..4b7aeacb51a --- /dev/null +++ b/docs/source/debugger/expressions.rst @@ -0,0 +1,36 @@ +.. _debugger-expressions-list: + +Debugger Expressions Guide +========================== + + +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. + +| +| ( ) : 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 +| +| + + +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. |