diff options
Diffstat (limited to 'libc/sysdeps/linux/or1k/fpu_control.h')
-rw-r--r-- | libc/sysdeps/linux/or1k/fpu_control.h | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/or1k/fpu_control.h b/libc/sysdeps/linux/or1k/fpu_control.h new file mode 100644 index 000000000..9abde4f42 --- /dev/null +++ b/libc/sysdeps/linux/or1k/fpu_control.h @@ -0,0 +1,88 @@ +/* FPU control word bits. OpenRISC version. + Copyright (C) 2024-2025 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library. If not, see + <https://www.gnu.org/licenses/>. */ + +#ifndef _FPU_CONTROL_H +#define _FPU_CONTROL_H + +#ifndef __or1k_hard_float__ + +# define _FPU_RESERVED 0xffffffff +# define _FPU_DEFAULT 0x00000000 +# define _FPU_GETCW(cw) (cw) = 0 +# define _FPU_SETCW(cw) (void) (cw) + +#else /* __or1k_hard_float__ */ + +/* Layout of FPCSR: + + The bits of the FPCSR are defined as follows, this should help + explain how the masks below have come to be. + + +-----------+----------------------------+-----+----+ + | 32 - 12 | 11 10 9 8 7 6 5 4 3 | 2-1 | 0 | + +-----------+----------------------------+-----+----+ + | Reserved | DZ IN IV IX Z QN SN UN OV | RM | EE | + +-----------+----------------------------+-----+----+ + + Exception flags: + + DZ - divide by zero flag. + IN - infinite flag. + IV - invalid flag. + IX - inexact flag. + Z - zero flag. + QN - qnan flag. + SN - snan flag. + UN - underflow flag. + OV - overflow flag. + + Rounding modes: + + The FPCSR bits 2-1 labeled above as RM specify the rounding mode. + + 00 - round to nearest + 01 - round to zero + 10 - round to positive infinity + 11 - round to negative infinity + + Enabling exceptions: + + EE - set to enable FPU exceptions. + + */ + +# define _FPU_RESERVED 0xfffff000 +/* Default: rounding to nearest with exceptions disabled. */ +# define _FPU_DEFAULT 0 +/* IEEE: Same as above with exceptions enabled. */ +# define _FPU_IEEE (_FPU_DEFAULT | 1) + +# define _FPU_FPCSR_RM_MASK (0x3 << 1) + +/* Macros for accessing the hardware control word. */ +# define _FPU_GETCW(cw) __asm__ volatile ("l.mfspr %0,r0,20" : "=r" (cw)) +# define _FPU_SETCW(cw) __asm__ volatile ("l.mtspr r0,%0,20" : : "r" (cw)) + +#endif /* __or1k_hard_float__ */ + +/* Type of the control word. */ +typedef unsigned int fpu_control_t; + +/* Default control word set at startup. */ +extern fpu_control_t __fpu_control; + +#endif /* fpu_control.h */ |