[ARM] 4436/1: PXA: move low IRQ initialization code to pxa_init_irq_low()
[linux-2.6] / arch / sparc / kernel / muldiv.c
1 /* $Id: muldiv.c,v 1.5 1997/12/15 20:07:20 ecd Exp $
2  * muldiv.c: Hardware multiply/division illegal instruction trap
3  *              for sun4c/sun4 (which do not have those instructions)
4  *
5  * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
6  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
7  *
8  * 2004-12-25   Krzysztof Helt (krzysztof.h1@wp.pl) 
9  *              - fixed registers constrains in inline assembly declarations
10  */
11
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/mm.h>
15 #include <asm/ptrace.h>
16 #include <asm/processor.h>
17 #include <asm/system.h>
18 #include <asm/uaccess.h>
19
20 /* #define DEBUG_MULDIV */
21
22 static inline int has_imm13(int insn)
23 {
24         return (insn & 0x2000);
25 }
26
27 static inline int is_foocc(int insn)
28 {
29         return (insn & 0x800000);
30 }
31
32 static inline int sign_extend_imm13(int imm)
33 {
34         return imm << 19 >> 19;
35 }
36
37 static inline void advance(struct pt_regs *regs)
38 {
39         regs->pc   = regs->npc;
40         regs->npc += 4;
41 }
42
43 static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
44                                        unsigned int rd)
45 {
46         if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
47                 /* Wheee... */
48                 __asm__ __volatile__("save %sp, -0x40, %sp\n\t"
49                                      "save %sp, -0x40, %sp\n\t"
50                                      "save %sp, -0x40, %sp\n\t"
51                                      "save %sp, -0x40, %sp\n\t"
52                                      "save %sp, -0x40, %sp\n\t"
53                                      "save %sp, -0x40, %sp\n\t"
54                                      "save %sp, -0x40, %sp\n\t"
55                                      "restore; restore; restore; restore;\n\t"
56                                      "restore; restore; restore;\n\t");
57         }
58 }
59
60 #define fetch_reg(reg, regs) ({                                         \
61         struct reg_window __user *win;                                  \
62         register unsigned long ret;                                     \
63                                                                         \
64         if (!(reg)) ret = 0;                                            \
65         else if ((reg) < 16) {                                          \
66                 ret = regs->u_regs[(reg)];                              \
67         } else {                                                        \
68                 /* Ho hum, the slightly complicated case. */            \
69                 win = (struct reg_window __user *)regs->u_regs[UREG_FP];\
70                 if (get_user (ret, &win->locals[(reg) - 16])) return -1;\
71         }                                                               \
72         ret;                                                            \
73 })
74
75 static inline int
76 store_reg(unsigned int result, unsigned int reg, struct pt_regs *regs)
77 {
78         struct reg_window __user *win;
79
80         if (!reg)
81                 return 0;
82         if (reg < 16) {
83                 regs->u_regs[reg] = result;
84                 return 0;
85         } else {
86                 /* need to use put_user() in this case: */
87                 win = (struct reg_window __user *) regs->u_regs[UREG_FP];
88                 return (put_user(result, &win->locals[reg - 16]));
89         }
90 }
91                 
92 extern void handle_hw_divzero (struct pt_regs *regs, unsigned long pc,
93                                unsigned long npc, unsigned long psr);
94
95 /* Should return 0 if mul/div emulation succeeded and SIGILL should
96  * not be issued.
97  */
98 int do_user_muldiv(struct pt_regs *regs, unsigned long pc)
99 {
100         unsigned int insn;
101         int inst;
102         unsigned int rs1, rs2, rdv;
103
104         if (!pc)
105                 return -1; /* This happens to often, I think */
106         if (get_user (insn, (unsigned int __user *)pc))
107                 return -1;
108         if ((insn & 0xc1400000) != 0x80400000)
109                 return -1;
110         inst = ((insn >> 19) & 0xf);
111         if ((inst & 0xe) != 10 && (inst & 0xe) != 14)
112                 return -1;
113
114         /* Now we know we have to do something with umul, smul, udiv or sdiv */
115         rs1 = (insn >> 14) & 0x1f;
116         rs2 = insn & 0x1f;
117         rdv = (insn >> 25) & 0x1f;
118         if (has_imm13(insn)) {
119                 maybe_flush_windows(rs1, 0, rdv);
120                 rs2 = sign_extend_imm13(insn);
121         } else {
122                 maybe_flush_windows(rs1, rs2, rdv);
123                 rs2 = fetch_reg(rs2, regs);
124         }
125         rs1 = fetch_reg(rs1, regs);
126         switch (inst) {
127         case 10: /* umul */
128 #ifdef DEBUG_MULDIV     
129                 printk ("unsigned muldiv: 0x%x * 0x%x = ", rs1, rs2);
130 #endif          
131                 __asm__ __volatile__ ("\n\t"
132                         "mov    %0, %%o0\n\t"
133                         "call   .umul\n\t"
134                         " mov   %1, %%o1\n\t"
135                         "mov    %%o0, %0\n\t"
136                         "mov    %%o1, %1\n\t"
137                         : "=r" (rs1), "=r" (rs2)
138                         : "0" (rs1), "1" (rs2)
139                         : "o0", "o1", "o2", "o3", "o4", "o5", "o7", "cc");
140 #ifdef DEBUG_MULDIV
141                 printk ("0x%x%08x\n", rs2, rs1);
142 #endif
143                 if (store_reg(rs1, rdv, regs))
144                         return -1;
145                 regs->y = rs2;
146                 break;
147         case 11: /* smul */
148 #ifdef DEBUG_MULDIV
149                 printk ("signed muldiv: 0x%x * 0x%x = ", rs1, rs2);
150 #endif
151                 __asm__ __volatile__ ("\n\t"
152                         "mov    %0, %%o0\n\t"
153                         "call   .mul\n\t"
154                         " mov   %1, %%o1\n\t"
155                         "mov    %%o0, %0\n\t"
156                         "mov    %%o1, %1\n\t"
157                         : "=r" (rs1), "=r" (rs2)
158                         : "0" (rs1), "1" (rs2)
159                         : "o0", "o1", "o2", "o3", "o4", "o5", "o7", "cc");
160 #ifdef DEBUG_MULDIV
161                 printk ("0x%x%08x\n", rs2, rs1);
162 #endif
163                 if (store_reg(rs1, rdv, regs))
164                         return -1;
165                 regs->y = rs2;
166                 break;
167         case 14: /* udiv */
168 #ifdef DEBUG_MULDIV
169                 printk ("unsigned muldiv: 0x%x%08x / 0x%x = ", regs->y, rs1, rs2);
170 #endif
171                 if (!rs2) {
172 #ifdef DEBUG_MULDIV
173                         printk ("DIVISION BY ZERO\n");
174 #endif
175                         handle_hw_divzero (regs, pc, regs->npc, regs->psr);
176                         return 0;
177                 }
178                 __asm__ __volatile__ ("\n\t"
179                         "mov    %2, %%o0\n\t"
180                         "mov    %0, %%o1\n\t"
181                         "mov    %%g0, %%o2\n\t"
182                         "call   __udivdi3\n\t"
183                         " mov   %1, %%o3\n\t"
184                         "mov    %%o1, %0\n\t"
185                         "mov    %%o0, %1\n\t"
186                         : "=r" (rs1), "=r" (rs2)
187                         : "r" (regs->y), "0" (rs1), "1" (rs2)
188                         : "o0", "o1", "o2", "o3", "o4", "o5", "o7",
189                           "g1", "g2", "g3", "cc");
190 #ifdef DEBUG_MULDIV
191                 printk ("0x%x\n", rs1);
192 #endif
193                 if (store_reg(rs1, rdv, regs))
194                         return -1;
195                 break;
196         case 15: /* sdiv */
197 #ifdef DEBUG_MULDIV
198                 printk ("signed muldiv: 0x%x%08x / 0x%x = ", regs->y, rs1, rs2);
199 #endif
200                 if (!rs2) {
201 #ifdef DEBUG_MULDIV
202                         printk ("DIVISION BY ZERO\n");
203 #endif
204                         handle_hw_divzero (regs, pc, regs->npc, regs->psr);
205                         return 0;
206                 }
207                 __asm__ __volatile__ ("\n\t"
208                         "mov    %2, %%o0\n\t"
209                         "mov    %0, %%o1\n\t"
210                         "mov    %%g0, %%o2\n\t"
211                         "call   __divdi3\n\t"
212                         " mov   %1, %%o3\n\t"
213                         "mov    %%o1, %0\n\t"
214                         "mov    %%o0, %1\n\t"
215                         : "=r" (rs1), "=r" (rs2)
216                         : "r" (regs->y), "0" (rs1), "1" (rs2)
217                         : "o0", "o1", "o2", "o3", "o4", "o5", "o7",
218                           "g1", "g2", "g3", "cc");
219 #ifdef DEBUG_MULDIV
220                 printk ("0x%x\n", rs1);
221 #endif
222                 if (store_reg(rs1, rdv, regs))
223                         return -1;
224                 break;
225         }
226         if (is_foocc (insn)) {
227                 regs->psr &= ~PSR_ICC;
228                 if ((inst & 0xe) == 14) {
229                         /* ?div */
230                         if (rs2) regs->psr |= PSR_V;
231                 }
232                 if (!rs1) regs->psr |= PSR_Z;
233                 if (((int)rs1) < 0) regs->psr |= PSR_N;
234 #ifdef DEBUG_MULDIV
235                 printk ("psr muldiv: %08x\n", regs->psr);
236 #endif
237         }
238         advance(regs);
239         return 0;
240 }