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b2e11d00e0
* Missed a couple escape sequences. (nw) * A little more escaping, acronym fixes, fix oddity in symlist (nw) * Update debugger internal help to match docs (nw) * Lowercasing for CPU in command parameters, fix casing on ASCII. (nw)
49 lines
2.1 KiB
ReStructuredText
49 lines
2.1 KiB
ReStructuredText
.. _debugger-expressions-list:
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Debugger Expressions Guide
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==========================
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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.
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| ( ) : standard parentheses
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| ++ -- : postfix increment/decrement
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| ++ -- ~ ! - + b@ w@ d@ q@ : prefix inc/dec, binary NOT, logical NOT, unary +/-, memory access
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| * / % : multiply, divide, modulus
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| + - : add, subtract
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| << >> : shift left/right
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| < <= > >= : less than, less than or equal, greater than, greater than or equal
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| == != : equal, not equal
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| & : binary AND
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| ^ : binary XOR
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| | : binary OR
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| && : logical AND
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| || : logical OR
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| = \*= /= %= += -= <<= >>= &= \|= ^= : assignment
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| , : separate terms, function parameters
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Differences from C Behaviors
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----------------------------
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- First, all math is performed on full 64-bit unsigned values, so things like **a < 0** won't work as expected.
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- Second, the logical operators **&&** and **||** do not have short-circuit properties -- both halves are always evaluated.
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- Finally, the new memory operators work like this:
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- **b!<addr>** refers to the byte at <addr> but does *NOT* suppress side effects such as reading a mailbox clearing the pending flag, or reading a FIFO removing an item.
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- **b@<addr>** refers to the byte at <addr> while suppressing side effects.
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- Similarly, **w@** and **w!** refer to a *word* in memory, **d@** and **d!** refer to a *dword* in memory, and **q@** and **q!** refer to a *qword* in memory.
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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'.
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As such, **dw\@300** refers to data memory word at address 300 and **id\@400** refers to an I/O memory dword at address 400.
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