File: /usr/src/linux/include/asm-alpha/fpu.h
1 #ifndef __ASM_ALPHA_FPU_H
2 #define __ASM_ALPHA_FPU_H
3
4 /*
5 * Alpha floating-point control register defines:
6 */
7 #define FPCR_DNOD (1UL<<47) /* denorm INV trap disable */
8 #define FPCR_DNZ (1UL<<48) /* denorms to zero */
9 #define FPCR_INVD (1UL<<49) /* invalid op disable (opt.) */
10 #define FPCR_DZED (1UL<<50) /* division by zero disable (opt.) */
11 #define FPCR_OVFD (1UL<<51) /* overflow disable (optional) */
12 #define FPCR_INV (1UL<<52) /* invalid operation */
13 #define FPCR_DZE (1UL<<53) /* division by zero */
14 #define FPCR_OVF (1UL<<54) /* overflow */
15 #define FPCR_UNF (1UL<<55) /* underflow */
16 #define FPCR_INE (1UL<<56) /* inexact */
17 #define FPCR_IOV (1UL<<57) /* integer overflow */
18 #define FPCR_UNDZ (1UL<<60) /* underflow to zero (opt.) */
19 #define FPCR_UNFD (1UL<<61) /* underflow disable (opt.) */
20 #define FPCR_INED (1UL<<62) /* inexact disable (opt.) */
21 #define FPCR_SUM (1UL<<63) /* summary bit */
22
23 #define FPCR_DYN_SHIFT 58 /* first dynamic rounding mode bit */
24 #define FPCR_DYN_CHOPPED (0x0UL << FPCR_DYN_SHIFT) /* towards 0 */
25 #define FPCR_DYN_MINUS (0x1UL << FPCR_DYN_SHIFT) /* towards -INF */
26 #define FPCR_DYN_NORMAL (0x2UL << FPCR_DYN_SHIFT) /* towards nearest */
27 #define FPCR_DYN_PLUS (0x3UL << FPCR_DYN_SHIFT) /* towards +INF */
28 #define FPCR_DYN_MASK (0x3UL << FPCR_DYN_SHIFT)
29
30 #define FPCR_MASK 0xffff800000000000
31
32 /*
33 * IEEE trap enables are implemented in software. These per-thread
34 * bits are stored in the "flags" field of "struct thread_struct".
35 * Thus, the bits are defined so as not to conflict with the
36 * floating-point enable bit (which is architected). On top of that,
37 * we want to make these bits compatible with OSF/1 so
38 * ieee_set_fp_control() etc. can be implemented easily and
39 * compatibly. The corresponding definitions are in
40 * /usr/include/machine/fpu.h under OSF/1.
41 */
42 #define IEEE_TRAP_ENABLE_INV (1UL<<1) /* invalid op */
43 #define IEEE_TRAP_ENABLE_DZE (1UL<<2) /* division by zero */
44 #define IEEE_TRAP_ENABLE_OVF (1UL<<3) /* overflow */
45 #define IEEE_TRAP_ENABLE_UNF (1UL<<4) /* underflow */
46 #define IEEE_TRAP_ENABLE_INE (1UL<<5) /* inexact */
47 #define IEEE_TRAP_ENABLE_DNO (1UL<<6) /* denorm */
48 #define IEEE_TRAP_ENABLE_MASK (IEEE_TRAP_ENABLE_INV | IEEE_TRAP_ENABLE_DZE |\
49 IEEE_TRAP_ENABLE_OVF | IEEE_TRAP_ENABLE_UNF |\
50 IEEE_TRAP_ENABLE_INE | IEEE_TRAP_ENABLE_DNO)
51
52 /* Denorm and Underflow flushing */
53 #define IEEE_MAP_DMZ (1UL<<12) /* Map denorm inputs to zero */
54 #define IEEE_MAP_UMZ (1UL<<13) /* Map underflowed outputs to zero */
55
56 #define IEEE_MAP_MASK (IEEE_MAP_DMZ | IEEE_MAP_UMZ)
57
58 /* status bits coming from fpcr: */
59 #define IEEE_STATUS_INV (1UL<<17)
60 #define IEEE_STATUS_DZE (1UL<<18)
61 #define IEEE_STATUS_OVF (1UL<<19)
62 #define IEEE_STATUS_UNF (1UL<<20)
63 #define IEEE_STATUS_INE (1UL<<21)
64 #define IEEE_STATUS_DNO (1UL<<22)
65
66 #define IEEE_STATUS_MASK (IEEE_STATUS_INV | IEEE_STATUS_DZE | \
67 IEEE_STATUS_OVF | IEEE_STATUS_UNF | \
68 IEEE_STATUS_INE | IEEE_STATUS_DNO)
69
70 #define IEEE_SW_MASK (IEEE_TRAP_ENABLE_MASK | \
71 IEEE_STATUS_MASK | IEEE_MAP_MASK)
72
73 #define IEEE_CURRENT_RM_SHIFT 32
74 #define IEEE_CURRENT_RM_MASK (3UL<<IEEE_CURRENT_RM_SHIFT)
75
76 #define IEEE_STATUS_TO_EXCSUM_SHIFT 16
77
78 #define IEEE_INHERIT (1UL<<63) /* inherit on thread create? */
79
80 /*
81 * Convert the software IEEE trap enable and status bits into the
82 * hardware fpcr format.
83 *
84 * Digital Unix engineers receive my thanks for not defining the
85 * software bits identical to the hardware bits. The chip designers
86 * receive my thanks for making all the not-implemented fpcr bits
87 * RAZ forcing us to use system calls to read/write this value.
88 */
89
90 static inline unsigned long
91 ieee_swcr_to_fpcr(unsigned long sw)
92 {
93 unsigned long fp;
94 fp = (sw & IEEE_STATUS_MASK) << 35;
95 fp |= (sw & IEEE_MAP_DMZ) << 36;
96 fp |= (sw & IEEE_STATUS_MASK ? FPCR_SUM : 0);
97 fp |= (~sw & (IEEE_TRAP_ENABLE_INV
98 | IEEE_TRAP_ENABLE_DZE
99 | IEEE_TRAP_ENABLE_OVF)) << 48;
100 fp |= (~sw & (IEEE_TRAP_ENABLE_UNF | IEEE_TRAP_ENABLE_INE)) << 57;
101 fp |= (sw & IEEE_MAP_UMZ ? FPCR_UNDZ | FPCR_UNFD : 0);
102 fp |= (~sw & IEEE_TRAP_ENABLE_DNO) << 41;
103 return fp;
104 }
105
106 static inline unsigned long
107 ieee_fpcr_to_swcr(unsigned long fp)
108 {
109 unsigned long sw;
110 sw = (fp >> 35) & IEEE_STATUS_MASK;
111 sw |= (fp >> 36) & IEEE_MAP_DMZ;
112 sw |= (~fp >> 48) & (IEEE_TRAP_ENABLE_INV
113 | IEEE_TRAP_ENABLE_DZE
114 | IEEE_TRAP_ENABLE_OVF);
115 sw |= (~fp >> 57) & (IEEE_TRAP_ENABLE_UNF | IEEE_TRAP_ENABLE_INE);
116 sw |= (fp >> 47) & IEEE_MAP_UMZ;
117 sw |= (~fp >> 41) & IEEE_TRAP_ENABLE_DNO;
118 return sw;
119 }
120
121 #ifdef __KERNEL__
122
123 /* The following two functions don't need trapb/excb instructions
124 around the mf_fpcr/mt_fpcr instructions because (a) the kernel
125 never generates arithmetic faults and (b) call_pal instructions
126 are implied trap barriers. */
127
128 static inline unsigned long
129 rdfpcr(void)
130 {
131 unsigned long tmp, ret;
132
133 #if defined(__alpha_cix__) || defined(__alpha_fix__)
134 __asm__ __volatile__ (
135 "ftoit $f0,%0\n\t"
136 "mf_fpcr $f0\n\t"
137 "ftoit $f0,%1\n\t"
138 "itoft %0,$f0"
139 : "=r"(tmp), "=r"(ret));
140 #else
141 __asm__ __volatile__ (
142 "stt $f0,%0\n\t"
143 "mf_fpcr $f0\n\t"
144 "stt $f0,%1\n\t"
145 "ldt $f0,%0"
146 : "=m"(tmp), "=m"(ret));
147 #endif
148
149 return ret;
150 }
151
152 static inline void
153 wrfpcr(unsigned long val)
154 {
155 unsigned long tmp;
156
157 #if defined(__alpha_cix__) || defined(__alpha_fix__)
158 __asm__ __volatile__ (
159 "ftoit $f0,%0\n\t"
160 "itoft %1,$f0\n\t"
161 "mt_fpcr $f0\n\t"
162 "itoft %0,$f0"
163 : "=&r"(tmp) : "r"(val));
164 #else
165 __asm__ __volatile__ (
166 "stt $f0,%0\n\t"
167 "ldt $f0,%1\n\t"
168 "mt_fpcr $f0\n\t"
169 "ldt $f0,%0"
170 : "=m"(tmp) : "m"(val));
171 #endif
172 }
173
174 static inline unsigned long
175 swcr_update_status(unsigned long swcr, unsigned long fpcr)
176 {
177 /* EV6 implements most of the bits in hardware. Collect
178 the acrued exception bits from the real fpcr. */
179 if (implver() == IMPLVER_EV6) {
180 swcr &= ~IEEE_STATUS_MASK;
181 swcr |= (fpcr >> 35) & IEEE_STATUS_MASK;
182 }
183 return swcr;
184 }
185
186 extern unsigned long alpha_read_fp_reg (unsigned long reg);
187 extern void alpha_write_fp_reg (unsigned long reg, unsigned long val);
188 extern unsigned long alpha_read_fp_reg_s (unsigned long reg);
189 extern void alpha_write_fp_reg_s (unsigned long reg, unsigned long val);
190
191 #endif /* __KERNEL__ */
192
193 #endif /* __ASM_ALPHA_FPU_H */
194