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9797405789
Totally reworked both parseDecimal and parseDecimalDigit parseDecimalDigit no longer exists, as it could be replaced by an inline alternative in the 4 places it appeared. This saves one byte overall, as the inline version is 4 bytes, 1 byte more than a call, and removing the function saved 5 bytes. It has been reduced from between 52 and 35 cycles (35 on error, so we'd expect 52 cycles to be more common unless someone's really bad at programming) to 14 cycles, so 2-3 times faster. parseDecimal has been reduced by a byte, and now the main loop is just about twice as fast, but with increased overhead. To put this into perspective, if we ignore error cases: For decimals of length 1 it'll be 1.20x faster, for decimals of length 2, 1.41x faster, for length 3, 1.51x faster, for length 4, 1.57x faster, and for length 5 and above, at least 1.48x faster (even faster if there's leading zeroes or not the worst case scenario). I believe there is still room for improvement, since the first iteration can be nearly replaced with "ld l, c" since 0*10=0, but when I tried this I could either add a zero check into the main loop, adding around 40 cycles and 10 bytes, or add 20 bytes to the overhead, and I don't think either of those options are worth it. |
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| README.md | ||
User applications
This folder contains code designed to be "userspace" application. Unlike the kernel, which always stay in memory. Those apps here will more likely be loaded in RAM from storage, ran, then discarded so that another userspace program can be run.
That doesn't mean that you can't include that code in your kernel though, but you will typically not want to do that.
Userspace convention
We execute a userspace application by calling the address it's loaded into. This means: a userspace application is expected to return.
Whatever calls the userspace app (usually, it will be the shell), should set HL to a pointer to unparsed arguments in string form, null terminated.
The userspace application is expected to set A on return. 0 means success, non-zero means error.