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+instruction: 0.666
+runtime: 0.168
+syscall: 0.167
+
+
+
+Wrong floating-point emulation on AArch64 with FPCR set to zero
+
+On AArch64, with FPCR set to Zero (i.e., FPU set to IEEE-754 compliant mode), floating-point emulation does not produce the same results as real hardware (e.g., Raspberry Pi 3 with AArch64 Linux).
+
+I attached a sample that reproduces the issue. It divides `x` by `y` and puts the result in `r`. The expected result of the operation is `q`.
+
+Output on real hardware:
+=========================================================
+fpcr = 0x07000000.
+x = 0x03250f416dcdc6d0. y = 0x00029f4e5837c977. r = 0x7ff0000000000000. q = 0x43300fde9cbcf023.
+fpcr = 0x00000000.
+x = 0x03250f416dcdc6d0. y = 0x00029f4e5837c977. r = 0x43300fde9cbcf023. q = 0x43300fde9cbcf023.
+=========================================================
+
+Notice that after setting FPCR to zero, `r` equals `q`.
+
+Output on qemu 3.0.0 (Linux user-mode emulation):
+=========================================================
+fpcr = 0x07000000.
+x = 0x03250f416dcdc6d0. y = 0x00029f4e5837c977. r = 0x7ff0000000000000. q = 0x43300fde9cbcf023.
+fpcr = 0x00000000.
+x = 0x03250f416dcdc6d0. y = 0x00029f4e5837c977. r = 0x43300fde9cbcf024. q = 0x43300fde9cbcf023.
+=========================================================
+
+Notice that after setting FPCR to zero, `r` is not equal to `q`.
+
+Also notice that, using another proprietary operating system, the same issue arises between a real board and QEMU. This might be an issue in emulation of the AArch64 instruction "fdiv".
+
+Build command line: aarch64-linux-gnu-gcc -static -O0 -o sample1 sample1.c
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