a87eacc6ab
## Summary Ref https://github.com/crosspoint-reader/crosspoint-reader/pull/737 This PR further reduce ~25ms from rendering time, testing inside the Setting screen: ``` master: [68440] [GFX] Time = 73 ms from clearScreen to displayBuffer PR: [97806] [GFX] Time = 47 ms from clearScreen to displayBuffer ``` And in extreme case (fill the entire screen with black or gray color): ``` master: [1125] [ ] Test fillRectDither drawn in 327 ms [1347] [ ] Test fillRect drawn in 222 ms PR: [1334] [ ] Test fillRectDither drawn in 225 ms [1455] [ ] Test fillRect drawn in 121 ms ``` Note that https://github.com/crosspoint-reader/crosspoint-reader/pull/737 is NOT applied on top of this PR. But with 2 of them combined, it should reduce from 47ms --> 42ms ## Details This PR based on the fact that function calls are costly if the function is small enough. For example, this simple call: ``` int rotatedX = 0; int rotatedY = 0; rotateCoordinates(x, y, &rotatedX, &rotatedY); ``` Generated assembly code: <img width="771" height="215" alt="image" src="https://github.com/user-attachments/assets/37991659-3304-41c3-a3b2-fb967da53f82" /> This adds ~10 instructions just to prepare the registers prior to the function call, plus some more instructions for the function's epilogue/prologue. Inlining it removing all of these: <img width="1471" height="832" alt="image" src="https://github.com/user-attachments/assets/b67a22ee-93ba-4017-88ed-c973e28ec914" /> Of course, this optimization is not magic. It's only beneficial under 3 conditions: - The function is small, not in size, but in terms of effective instructions. For example, the `rotateCoordinates` is simply a jump table, where each branch is just 3-4 inst - The function has multiple input arguments, which requires some move to put it onto the correct place - The function is called very frequently (i.e. critical path) --- ### AI Usage While CrossPoint doesn't have restrictions on AI tools in contributing, please be transparent about their usage as it helps set the right context for reviewers. Did you use AI tools to help write this code? **NO**
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