xref: /openbmc/linux/arch/alpha/include/asm/fpu.h (revision 99a15348)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_ALPHA_FPU_H
3 #define __ASM_ALPHA_FPU_H
4 
5 #include <asm/special_insns.h>
6 #include <uapi/asm/fpu.h>
7 
8 /* The following two functions don't need trapb/excb instructions
9    around the mf_fpcr/mt_fpcr instructions because (a) the kernel
10    never generates arithmetic faults and (b) call_pal instructions
11    are implied trap barriers.  */
12 
13 static inline unsigned long
14 rdfpcr(void)
15 {
16 	unsigned long tmp, ret;
17 
18 #if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)
19 	__asm__ __volatile__ (
20 		"ftoit $f0,%0\n\t"
21 		"mf_fpcr $f0\n\t"
22 		"ftoit $f0,%1\n\t"
23 		"itoft %0,$f0"
24 		: "=r"(tmp), "=r"(ret));
25 #else
26 	__asm__ __volatile__ (
27 		"stt $f0,%0\n\t"
28 		"mf_fpcr $f0\n\t"
29 		"stt $f0,%1\n\t"
30 		"ldt $f0,%0"
31 		: "=m"(tmp), "=m"(ret));
32 #endif
33 
34 	return ret;
35 }
36 
37 static inline void
38 wrfpcr(unsigned long val)
39 {
40 	unsigned long tmp;
41 
42 #if defined(CONFIG_ALPHA_EV6) || defined(CONFIG_ALPHA_EV67)
43 	__asm__ __volatile__ (
44 		"ftoit $f0,%0\n\t"
45 		"itoft %1,$f0\n\t"
46 		"mt_fpcr $f0\n\t"
47 		"itoft %0,$f0"
48 		: "=&r"(tmp) : "r"(val));
49 #else
50 	__asm__ __volatile__ (
51 		"stt $f0,%0\n\t"
52 		"ldt $f0,%1\n\t"
53 		"mt_fpcr $f0\n\t"
54 		"ldt $f0,%0"
55 		: "=m"(tmp) : "m"(val));
56 #endif
57 }
58 
59 static inline unsigned long
60 swcr_update_status(unsigned long swcr, unsigned long fpcr)
61 {
62 	/* EV6 implements most of the bits in hardware.  Collect
63 	   the acrued exception bits from the real fpcr.  */
64 	if (implver() == IMPLVER_EV6) {
65 		swcr &= ~IEEE_STATUS_MASK;
66 		swcr |= (fpcr >> 35) & IEEE_STATUS_MASK;
67 	}
68 	return swcr;
69 }
70 
71 extern unsigned long alpha_read_fp_reg (unsigned long reg);
72 extern void alpha_write_fp_reg (unsigned long reg, unsigned long val);
73 extern unsigned long alpha_read_fp_reg_s (unsigned long reg);
74 extern void alpha_write_fp_reg_s (unsigned long reg, unsigned long val);
75 
76 #endif /* __ASM_ALPHA_FPU_H */
77