1 // Misc utility functions.
3 // Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
5 // This file may be distributed under the terms of the GNU LGPLv3 license.
7 #include "util.h" // call16
8 #include "bregs.h" // struct bregs
9 #include "config.h" // BUILD_STACK_ADDR
12 cpuid(u32 index, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
15 u32 origflags = save_flags();
16 restore_flags(origflags ^ F_ID);
17 u32 newflags = save_flags();
18 restore_flags(origflags);
20 if (((origflags ^ newflags) & F_ID) != F_ID)
22 *eax = *ebx = *ecx = *edx = 0;
24 __cpuid(index, eax, ebx, ecx, edx);
28 /****************************************************************
30 ****************************************************************/
32 // Call a function with a specified register state. Note that on
33 // return, the interrupt enable/disable flag may be altered.
35 call16(struct bregs *callregs)
37 if (!MODESEGMENT && getesp() > BUILD_STACK_ADDR)
38 panic("call16 with invalid stack\n");
45 "calll __call16_from32"
47 : "+a" (callregs), "+m" (*callregs)
49 : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory");
53 call16big(struct bregs *callregs)
56 if (getesp() > BUILD_STACK_ADDR)
57 panic("call16 with invalid stack\n");
59 "calll __call16big_from32"
60 : "+a" (callregs), "+m" (*callregs)
62 : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory");
66 __call16_int(struct bregs *callregs, u16 offset)
69 callregs->code.seg = GET_SEG(CS);
71 callregs->code.seg = SEG_BIOS;
72 callregs->code.offset = offset;
77 /****************************************************************
79 ****************************************************************/
81 // Sum the bytes in the specified area.
83 checksum_far(u16 buf_seg, void *buf_far, u32 len)
89 sum += GET_VAR(ES, ((u8*)buf_far)[i]);
94 checksum(void *buf, u32 len)
96 return checksum_far(GET_SEG(SS), buf, len);
100 strlen(const char *s)
102 if (__builtin_constant_p(s))
103 return __builtin_strlen(s);
110 // Compare two areas of memory.
112 memcmp(const void *s1, const void *s2, size_t n)
115 if (*(u8*)s1 != *(u8*)s2)
116 return *(u8*)s1 < *(u8*)s2 ? -1 : 1;
124 // Compare two strings.
126 strcmp(const char *s1, const char *s2)
130 return *s1 < *s2 ? -1 : 1;
139 memset_far(u16 d_seg, void *d_far, u8 c, size_t len)
143 "rep stosb %%es:(%%di)"
144 : "+c"(len), "+D"(d_far)
150 memset16_far(u16 d_seg, void *d_far, u16 c, size_t len)
155 "rep stosw %%es:(%%di)"
156 : "+c"(len), "+D"(d_far)
162 memset(void *s, int c, size_t n)
165 ((char *)s)[--n] = c;
169 void memset_fl(void *ptr, u8 val, size_t size)
172 memset_far(FLATPTR_TO_SEG(ptr), (void*)(FLATPTR_TO_OFFSET(ptr)),
175 memset(ptr, val, size);
179 memcpy_far(u16 d_seg, void *d_far, u16 s_seg, const void *s_far, size_t len)
186 "rep movsb (%%si),%%es:(%%di)\n"
188 : "=&r"(bkup_ds), "+c"(len), "+S"(s_far), "+D"(d_far)
194 memcpy_fl(void *d_fl, const void *s_fl, size_t len)
197 memcpy_far(FLATPTR_TO_SEG(d_fl), (void*)FLATPTR_TO_OFFSET(d_fl)
198 , FLATPTR_TO_SEG(s_fl), (void*)FLATPTR_TO_OFFSET(s_fl)
201 memcpy(d_fl, s_fl, len);
206 memcpy(void *d1, const void *s1, size_t len)
208 #define memcpy __builtin_memcpy
211 SET_SEG(ES, GET_SEG(SS));
213 if (((u32)d1 | (u32)s1 | len) & 3) {
214 // non-aligned memcpy
216 "rep movsb (%%esi),%%es:(%%edi)"
217 : "+c"(len), "+S"(s1), "+D"(d)
221 // Common case - use 4-byte copy
224 "rep movsl (%%esi),%%es:(%%edi)"
225 : "+c"(len), "+S"(s1), "+D"(d)
230 // Copy to/from memory mapped IO. IO mem is very slow, so yield
233 iomemcpy(void *d, const void *s, u32 len)
243 "rep movsl (%%esi),%%es:(%%edi)"
244 : "+c"(copylen), "+S"(s), "+D"(d)
249 // Copy any remaining bytes.
254 memmove(void *d, const void *s, size_t len)
257 return memcpy(d, s, len);
262 *(char*)d = *(char*)s;
270 // Copy a string - truncating it if necessary.
272 strtcpy(char *dest, const char *src, size_t len)
275 while (--len && *src != '\0')
281 // locate first occurance of character c in the string s
283 strchr(const char *s, int c)
291 // Remove any trailing blank characters (spaces, new lines, carriage returns)
293 nullTrailingSpace(char *buf)
295 int len = strlen(buf);
296 char *end = &buf[len-1];
297 while (end >= buf && *end <= ' ')
301 /****************************************************************
303 ****************************************************************/
305 // See if a keystroke is pending in the keyboard buffer.
307 check_for_keystroke(void)
310 memset(&br, 0, sizeof(br));
313 call16_int(0x16, &br);
314 return !(br.flags & F_ZF);
317 // Return a keystroke - waiting forever if necessary.
319 get_raw_keystroke(void)
322 memset(&br, 0, sizeof(br));
324 call16_int(0x16, &br);
328 // Read a keystroke - waiting up to 'msec' milliseconds.
330 get_keystroke(int msec)
332 u32 end = calc_future_timer(msec);
334 if (check_for_keystroke())
335 return get_raw_keystroke();
336 if (check_timer(end))