-#include "util.h" // usleep
-
-// Sleep for n microseconds. currently using the
-// refresh request port 0x61 bit4, toggling every 15usec
-void
-usleep(u32 count)
-{
- count = count / 15;
- u8 kbd = inb(PORT_PS2_CTRLB);
- while (count)
- if ((inb(PORT_PS2_CTRLB) ^ kbd) & KBD_REFRESH)
- count--;
+// Misc utility functions.
+//
+// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+
+#include "util.h" // call16
+#include "bregs.h" // struct bregs
+#include "farptr.h" // GET_FLATPTR
+#include "biosvar.h" // get_ebda_seg
+
+// Call a function with a specified register state. Note that on
+// return, the interrupt enable/disable flag may be altered.
+inline void
+call16(struct bregs *callregs)
+{
+ asm volatile(
+#if MODE16 == 1
+ "calll __call16\n"
+#else
+ "calll __call16_from32\n"
+#endif
+ : "+a" (callregs), "+m" (*callregs)
+ :
+ : "ebx", "ecx", "edx", "esi", "edi", "ebp", "cc", "memory");
+}
+
+inline void
+call16big(struct bregs *callregs)
+{
+ extern void __force_link_error__call16big_only_in_32bit_mode();
+ if (MODE16)
+ __force_link_error__call16big_only_in_32bit_mode();
+
+ asm volatile(
+ "calll __call16big_from32\n"
+ : "+a" (callregs), "+m" (*callregs)
+ :
+ : "ebx", "ecx", "edx", "esi", "edi", "ebp", "cc", "memory");
+}
+
+inline void
+__call16_int(struct bregs *callregs, u16 offset)
+{
+ if (MODE16)
+ callregs->cs = GET_SEG(CS);
+ else
+ callregs->cs = SEG_BIOS;
+ callregs->ip = offset;
+ call16(callregs);
+}
+
+inline void
+call16_simpint(int nr, u32 *eax, u32 *flags)
+{
+ extern void __force_link_error__call16_simpint_only_in_16bit_mode();
+ if (!MODE16)
+ __force_link_error__call16_simpint_only_in_16bit_mode();
+
+ asm volatile(
+ "stc\n"
+ "int %2\n"
+ "pushfl\n"
+ "popl %1\n"
+ "cld\n"
+ "cli\n"
+ : "+a"(*eax), "=r"(*flags)
+ : "i"(nr)
+ : "cc", "memory");
+}
+
+// Switch to the extra stack in ebda and call a function.
+inline u32
+stack_hop(u32 eax, u32 edx, u32 ecx, void *func)
+{
+ extern void __force_link_error__stack_hop_only_in_16bit_mode();
+ if (!MODE16)
+ __force_link_error__stack_hop_only_in_16bit_mode();
+
+ u16 ebda_seg = get_ebda_seg(), bkup_ss;
+ u32 bkup_esp;
+ asm volatile(
+ // Backup current %ss/%esp values.
+ "movw %%ss, %w3\n"
+ "movl %%esp, %4\n"
+ // Copy ebda seg to %ds/%ss and set %esp
+ "movw %w6, %%ds\n"
+ "movw %w6, %%ss\n"
+ "movl %5, %%esp\n"
+ // Call func
+ "calll %7\n"
+ // Restore segments and stack
+ "movw %w3, %%ds\n"
+ "movw %w3, %%ss\n"
+ "movl %4, %%esp\n"
+ : "+a" (eax), "+d" (edx), "+c" (ecx), "=&r" (bkup_ss), "=&r" (bkup_esp)
+ : "i" (EBDA_OFFSET_TOP_STACK), "r" (ebda_seg), "m" (*(u8*)func)
+ : "cc", "memory");
+ return eax;
+}
+
+// Sum the bytes in the specified area.
+u8
+checksum_far(u16 buf_seg, u8 *buf_far, u32 len)
+{
+ SET_SEG(ES, buf_seg);
+ u32 i;
+ u8 sum = 0;
+ for (i=0; i<len; i++)
+ sum += GET_VAR(ES, buf_far[i]);
+ return sum;
+}
+
+u8
+checksum(u8 *buf, u32 len)
+{
+ return checksum_far(GET_SEG(SS), buf, len);
+}
+
+void *
+memset(void *s, int c, size_t n)
+{
+ while (n)
+ ((char *)s)[--n] = c;
+ return s;
+}
+
+inline void
+memcpy_far(u16 d_seg, void *d_far, u16 s_seg, const void *s_far, size_t len)
+{
+ SET_SEG(ES, d_seg);
+ u16 bkup_ds;
+ asm volatile(
+ "movw %%ds, %w0\n"
+ "movw %w4, %%ds\n"
+ "rep movsb (%%si),%%es:(%%di)\n"
+ "movw %w0, %%ds\n"
+ : "=&r"(bkup_ds), "+c"(len), "+S"(s_far), "+D"(d_far)
+ : "r"(s_seg)
+ : "cc", "memory");
+}
+
+void *
+memcpy(void *d1, const void *s1, size_t len)
+{
+ u8 *d = (u8*)d1, *s = (u8*)s1;
+ while (len--)
+ *d++ = *s++;
+ return d1;
+}
+
+void *
+memmove(void *d, const void *s, size_t len)
+{
+ if (s >= d)
+ return memcpy(d, s, len);
+
+ d += len-1;
+ s += len-1;
+ while (len--) {
+ *(char*)d = *(char*)s;
+ d--;
+ s--;
+ }
+
+ return d;
+}
+
+// Copy a string - truncating it if necessary.
+char *
+strtcpy(char *dest, const char *src, size_t len)
+{
+ char *d = dest;
+ while (len-- && *src != '\0')
+ *d++ = *src++;
+ *d = '\0';
+ return dest;
+}
+
+// Wait for 'usec' microseconds with irqs enabled.
+static void
+usleep(u32 usec)
+{
+ struct bregs br;
+ memset(&br, 0, sizeof(br));
+ br.ah = 0x86;
+ br.cx = usec >> 16;
+ br.dx = usec;
+ call16_int(0x15, &br);
+}
+
+// See if a keystroke is pending in the keyboard buffer.
+static int
+check_for_keystroke()
+{
+ struct bregs br;
+ memset(&br, 0, sizeof(br));
+ br.ah = 1;
+ call16_int(0x16, &br);
+ return !(br.flags & F_ZF);
+}
+
+// Return a keystroke - waiting forever if necessary.
+static int
+get_raw_keystroke()
+{
+ struct bregs br;
+ memset(&br, 0, sizeof(br));
+ call16_int(0x16, &br);
+ return br.ah;
+}
+
+// Read a keystroke - waiting up to 'msec' milliseconds.
+int
+get_keystroke(int msec)
+{
+ for (;;) {
+ if (check_for_keystroke())
+ return get_raw_keystroke();
+ if (msec <= 0)
+ return -1;
+ usleep(50*1000);
+ msec -= 50;
+ }
}
projects / seabios.git / blobdiff