xref: /openbmc/linux/arch/alpha/include/uapi/asm/fpu.h (revision 6f52b16c)
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _UAPI__ASM_ALPHA_FPU_H
3 #define _UAPI__ASM_ALPHA_FPU_H
4 
5 
6 /*
7  * Alpha floating-point control register defines:
8  */
9 #define FPCR_DNOD	(1UL<<47)	/* denorm INV trap disable */
10 #define FPCR_DNZ	(1UL<<48)	/* denorms to zero */
11 #define FPCR_INVD	(1UL<<49)	/* invalid op disable (opt.) */
12 #define FPCR_DZED	(1UL<<50)	/* division by zero disable (opt.) */
13 #define FPCR_OVFD	(1UL<<51)	/* overflow disable (optional) */
14 #define FPCR_INV	(1UL<<52)	/* invalid operation */
15 #define FPCR_DZE	(1UL<<53)	/* division by zero */
16 #define FPCR_OVF	(1UL<<54)	/* overflow */
17 #define FPCR_UNF	(1UL<<55)	/* underflow */
18 #define FPCR_INE	(1UL<<56)	/* inexact */
19 #define FPCR_IOV	(1UL<<57)	/* integer overflow */
20 #define FPCR_UNDZ	(1UL<<60)	/* underflow to zero (opt.) */
21 #define FPCR_UNFD	(1UL<<61)	/* underflow disable (opt.) */
22 #define FPCR_INED	(1UL<<62)	/* inexact disable (opt.) */
23 #define FPCR_SUM	(1UL<<63)	/* summary bit */
24 
25 #define FPCR_DYN_SHIFT	58		/* first dynamic rounding mode bit */
26 #define FPCR_DYN_CHOPPED (0x0UL << FPCR_DYN_SHIFT)	/* towards 0 */
27 #define FPCR_DYN_MINUS	 (0x1UL << FPCR_DYN_SHIFT)	/* towards -INF */
28 #define FPCR_DYN_NORMAL	 (0x2UL << FPCR_DYN_SHIFT)	/* towards nearest */
29 #define FPCR_DYN_PLUS	 (0x3UL << FPCR_DYN_SHIFT)	/* towards +INF */
30 #define FPCR_DYN_MASK	 (0x3UL << FPCR_DYN_SHIFT)
31 
32 #define FPCR_MASK	0xffff800000000000L
33 
34 /*
35  * IEEE trap enables are implemented in software.  These per-thread
36  * bits are stored in the "ieee_state" field of "struct thread_info".
37  * Thus, the bits are defined so as not to conflict with the
38  * floating-point enable bit (which is architected).  On top of that,
39  * we want to make these bits compatible with OSF/1 so
40  * ieee_set_fp_control() etc. can be implemented easily and
41  * compatibly.  The corresponding definitions are in
42  * /usr/include/machine/fpu.h under OSF/1.
43  */
44 #define IEEE_TRAP_ENABLE_INV	(1UL<<1)	/* invalid op */
45 #define IEEE_TRAP_ENABLE_DZE	(1UL<<2)	/* division by zero */
46 #define IEEE_TRAP_ENABLE_OVF	(1UL<<3)	/* overflow */
47 #define IEEE_TRAP_ENABLE_UNF	(1UL<<4)	/* underflow */
48 #define IEEE_TRAP_ENABLE_INE	(1UL<<5)	/* inexact */
49 #define IEEE_TRAP_ENABLE_DNO	(1UL<<6)	/* denorm */
50 #define IEEE_TRAP_ENABLE_MASK	(IEEE_TRAP_ENABLE_INV | IEEE_TRAP_ENABLE_DZE |\
51 				 IEEE_TRAP_ENABLE_OVF | IEEE_TRAP_ENABLE_UNF |\
52 				 IEEE_TRAP_ENABLE_INE | IEEE_TRAP_ENABLE_DNO)
53 
54 /* Denorm and Underflow flushing */
55 #define IEEE_MAP_DMZ		(1UL<<12)	/* Map denorm inputs to zero */
56 #define IEEE_MAP_UMZ		(1UL<<13)	/* Map underflowed outputs to zero */
57 
58 #define IEEE_MAP_MASK		(IEEE_MAP_DMZ | IEEE_MAP_UMZ)
59 
60 /* status bits coming from fpcr: */
61 #define IEEE_STATUS_INV		(1UL<<17)
62 #define IEEE_STATUS_DZE		(1UL<<18)
63 #define IEEE_STATUS_OVF		(1UL<<19)
64 #define IEEE_STATUS_UNF		(1UL<<20)
65 #define IEEE_STATUS_INE		(1UL<<21)
66 #define IEEE_STATUS_DNO		(1UL<<22)
67 
68 #define IEEE_STATUS_MASK	(IEEE_STATUS_INV | IEEE_STATUS_DZE |	\
69 				 IEEE_STATUS_OVF | IEEE_STATUS_UNF |	\
70 				 IEEE_STATUS_INE | IEEE_STATUS_DNO)
71 
72 #define IEEE_SW_MASK		(IEEE_TRAP_ENABLE_MASK |		\
73 				 IEEE_STATUS_MASK | IEEE_MAP_MASK)
74 
75 #define IEEE_CURRENT_RM_SHIFT	32
76 #define IEEE_CURRENT_RM_MASK	(3UL<<IEEE_CURRENT_RM_SHIFT)
77 
78 #define IEEE_STATUS_TO_EXCSUM_SHIFT	16
79 
80 #define IEEE_INHERIT    (1UL<<63)	/* inherit on thread create? */
81 
82 /*
83  * Convert the software IEEE trap enable and status bits into the
84  * hardware fpcr format.
85  *
86  * Digital Unix engineers receive my thanks for not defining the
87  * software bits identical to the hardware bits.  The chip designers
88  * receive my thanks for making all the not-implemented fpcr bits
89  * RAZ forcing us to use system calls to read/write this value.
90  */
91 
92 static inline unsigned long
ieee_swcr_to_fpcr(unsigned long sw)93 ieee_swcr_to_fpcr(unsigned long sw)
94 {
95 	unsigned long fp;
96 	fp = (sw & IEEE_STATUS_MASK) << 35;
97 	fp |= (sw & IEEE_MAP_DMZ) << 36;
98 	fp |= (sw & IEEE_STATUS_MASK ? FPCR_SUM : 0);
99 	fp |= (~sw & (IEEE_TRAP_ENABLE_INV
100 		      | IEEE_TRAP_ENABLE_DZE
101 		      | IEEE_TRAP_ENABLE_OVF)) << 48;
102 	fp |= (~sw & (IEEE_TRAP_ENABLE_UNF | IEEE_TRAP_ENABLE_INE)) << 57;
103 	fp |= (sw & IEEE_MAP_UMZ ? FPCR_UNDZ | FPCR_UNFD : 0);
104 	fp |= (~sw & IEEE_TRAP_ENABLE_DNO) << 41;
105 	return fp;
106 }
107 
108 static inline unsigned long
ieee_fpcr_to_swcr(unsigned long fp)109 ieee_fpcr_to_swcr(unsigned long fp)
110 {
111 	unsigned long sw;
112 	sw = (fp >> 35) & IEEE_STATUS_MASK;
113 	sw |= (fp >> 36) & IEEE_MAP_DMZ;
114 	sw |= (~fp >> 48) & (IEEE_TRAP_ENABLE_INV
115 			     | IEEE_TRAP_ENABLE_DZE
116 			     | IEEE_TRAP_ENABLE_OVF);
117 	sw |= (~fp >> 57) & (IEEE_TRAP_ENABLE_UNF | IEEE_TRAP_ENABLE_INE);
118 	sw |= (fp >> 47) & IEEE_MAP_UMZ;
119 	sw |= (~fp >> 41) & IEEE_TRAP_ENABLE_DNO;
120 	return sw;
121 }
122 
123 
124 #endif /* _UAPI__ASM_ALPHA_FPU_H */
125