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 /****************************************************************
14 ****************************************************************/
16 // Call a function with a specified register state. Note that on
17 // return, the interrupt enable/disable flag may be altered.
19 call16(struct bregs *callregs)
21 if (!MODESEGMENT && getesp() > BUILD_STACK_ADDR)
22 panic("call16 with invalid stack\n");
29 "calll __call16_from32"
31 : "+a" (callregs), "+m" (*callregs)
33 : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory");
37 call16big(struct bregs *callregs)
40 if (getesp() > BUILD_STACK_ADDR)
41 panic("call16 with invalid stack\n");
43 "calll __call16big_from32"
44 : "+a" (callregs), "+m" (*callregs)
46 : "ebx", "ecx", "edx", "esi", "edi", "cc", "memory");
50 __call16_int(struct bregs *callregs, u16 offset)
53 callregs->code.seg = GET_SEG(CS);
55 callregs->code.seg = SEG_BIOS;
56 callregs->code.offset = offset;
60 // 16bit trampoline for enabling irqs from 32bit mode.
62 " .global trampoline_checkirqs\n"
63 "trampoline_checkirqs:\n"
80 extern void trampoline_checkirqs();
83 br.code.seg = SEG_BIOS;
84 br.code.offset = (u32)&trampoline_checkirqs;
90 /****************************************************************
92 ****************************************************************/
94 // Sum the bytes in the specified area.
96 checksum_far(u16 buf_seg, void *buf_far, u32 len)
101 for (i=0; i<len; i++)
102 sum += GET_VAR(ES, ((u8*)buf_far)[i]);
107 checksum(void *buf, u32 len)
109 return checksum_far(GET_SEG(SS), buf, len);
113 strlen(const char *s)
115 if (__builtin_constant_p(s))
116 return __builtin_strlen(s);
123 // Compare two areas of memory.
125 memcmp(const void *s1, const void *s2, size_t n)
128 if (*(u8*)s1 != *(u8*)s2)
129 return *(u8*)s1 < *(u8*)s2 ? -1 : 1;
137 // Compare two strings.
139 strcmp(const char *s1, const char *s2)
143 return *s1 < *s2 ? -1 : 1;
152 memset_far(u16 d_seg, void *d_far, u8 c, size_t len)
156 "rep stosb %%es:(%%di)"
157 : "+c"(len), "+D"(d_far)
163 memset16_far(u16 d_seg, void *d_far, u16 c, size_t len)
168 "rep stosw %%es:(%%di)"
169 : "+c"(len), "+D"(d_far)
175 memset(void *s, int c, size_t n)
178 ((char *)s)[--n] = c;
183 memcpy_far(u16 d_seg, void *d_far, u16 s_seg, const void *s_far, size_t len)
190 "rep movsb (%%si),%%es:(%%di)\n"
192 : "=&r"(bkup_ds), "+c"(len), "+S"(s_far), "+D"(d_far)
199 memcpy(void *d1, const void *s1, size_t len)
201 #define memcpy __builtin_memcpy
204 SET_SEG(ES, GET_SEG(SS));
206 if (((u32)d1 | (u32)s1 | len) & 3) {
207 // non-aligned memcpy
209 "rep movsb (%%esi),%%es:(%%edi)"
210 : "+c"(len), "+S"(s1), "+D"(d)
214 // Common case - use 4-byte copy
217 "rep movsl (%%esi),%%es:(%%edi)"
218 : "+c"(len), "+S"(s1), "+D"(d)
223 // Copy from memory mapped IO. IO mem is very slow, so yield
224 // periodically. 'len' must be 4 byte aligned.
226 iomemcpy(void *d, const void *s, u32 len)
236 "rep movsl (%%esi),%%es:(%%edi)"
237 : "+c"(copylen), "+S"(s), "+D"(d)
244 memmove(void *d, const void *s, size_t len)
247 return memcpy(d, s, len);
252 *(char*)d = *(char*)s;
260 // Copy a string - truncating it if necessary.
262 strtcpy(char *dest, const char *src, size_t len)
265 while (len-- && *src != '\0')
272 /****************************************************************
274 ****************************************************************/
276 // Wait for 'usec' microseconds using (with irqs enabled) using int 1586.
281 memset(&br, 0, sizeof(br));
286 call16_int(0x15, &br);
289 // See if a keystroke is pending in the keyboard buffer.
291 check_for_keystroke()
294 memset(&br, 0, sizeof(br));
297 call16_int(0x16, &br);
298 return !(br.flags & F_ZF);
301 // Return a keystroke - waiting forever if necessary.
306 memset(&br, 0, sizeof(br));
308 call16_int(0x16, &br);
312 // Read a keystroke - waiting up to 'msec' milliseconds.
314 get_keystroke(int msec)
317 if (check_for_keystroke())
318 return get_raw_keystroke();