Commit 780a7a33 authored by Zach Fredin's avatar Zach Fredin

updated README.md

parent bdacf57b
......@@ -3,4 +3,4 @@ This test follows the standard [CBA pi benchmark](https://gitlab.cba.mit.edu/pub
![pi capture](pi_capture.png)
The measurement shows a total calculation time of 12.91 s, including a [for these purposes] negligible delay to toggle the GPIOs. The FPU is set up with flags `-mfloat-abi=hard -mfpu=fpv4-sp-d16`, while the compiler includes `-O3`. Based on the pi benchmark calculation rate of 5 FLOPS per cycle iteration, this test suggests the STM32F412 is running at (5 * 1E6) / (12.91) = 0.387 MFLOPS. At the current 84 MHz clock speed, this suggests the pi calculation is taking (8.4E7) / (1E6 / 12.91) = 1084 clock cycles per iteration. This is a few orders of magnitude high, suggesting the FPU isn't cooperating.
The measurement shows a total calculation time of 12.91 s, including a [for these purposes] negligible delay to toggle the GPIOs. The FPU is set up with flags `-mfloat-abi=hard -mfpu=fpv4-sp-d16`, while the compiler includes `-O3`. Based on the pi benchmark calculation rate of 5 FLOPS per cycle iteration, this test suggests the STM32F412 is running at (5 * 1E6) / (12.91) = 0.387 MFLOPS. At the current 84 MHz clock speed, this suggests the pi calculation is taking (8.4E7) / (1E6 / 12.91) = 1084 clock cycles per iteration. This is a few orders of magnitude high (based on 1 clock cycle add/subtract/multiply, 14 clock cycle divide), suggesting the FPU isn't cooperating.
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