From 2ba107f6795d780bb54b85040a9b2c6a60fccb15 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 29 Nov 2023 00:27:46 +1100 Subject: selftests/powerpc: Generate better bit patterns for FPU tests The fpu_preempt test randomly initialises an array of doubles to try and detect FPU register corruption. However the values it generates do not occupy the full range of values possible in the 64-bit double, meaning some partial register corruption could go undetected. Without getting too carried away, add some better initialisation to generate values that occupy more bits. Sample values before: f0 902677510 (raw 0x41cae6e203000000) f1 325217596 (raw 0x41b3626d3c000000) f2 1856578300 (raw 0x41dbaa48bf000000) f3 1247189984 (raw 0x41d295a6f8000000) And after: f0 1.1078153481413311e-09 (raw 0x3e13083932805cc2) f1 1.0576648474801922e+17 (raw 0x43777c20eb88c261) f2 -6.6245033413594075e-10 (raw 0xbe06c2f989facae9) f3 3.0085988827156291e+18 (raw 0x43c4e0585f2df37b) Signed-off-by: Michael Ellerman Link: https://msgid.link/20231128132748.1990179-3-mpe@ellerman.id.au --- tools/testing/selftests/powerpc/math/fpu.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 tools/testing/selftests/powerpc/math/fpu.h (limited to 'tools/testing/selftests/powerpc/math/fpu.h') diff --git a/tools/testing/selftests/powerpc/math/fpu.h b/tools/testing/selftests/powerpc/math/fpu.h new file mode 100644 index 000000000000..a8ad0d42604e --- /dev/null +++ b/tools/testing/selftests/powerpc/math/fpu.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright 2023, Michael Ellerman, IBM Corporation. + */ + +#ifndef _SELFTESTS_POWERPC_FPU_H +#define _SELFTESTS_POWERPC_FPU_H + +static inline void randomise_darray(double *darray, int num) +{ + long val; + + for (int i = 0; i < num; i++) { + val = random(); + if (val & 1) + val *= -1; + + if (val & 2) + darray[i] = 1.0 / val; + else + darray[i] = val * val; + } +} + +#endif /* _SELFTESTS_POWERPC_FPU_H */ -- cgit v1.2.3