Changeset 494 for trunk/src/emx/include/386/builtin.h

Timestamp:

Aug 1, 2003, 8:42:12 AM (22 years ago)

Author:

zap

Message:

See ChangeLog.

File:

• trunk/src/emx/include/386/builtin.h (modified) (1 diff, 1 prop)

trunk/src/emx/include/386/builtin.h

@@ -87 +87 @@
 }
 
+/* Quick routines similar to div() and friends, but inline */
+
+static __inline__ long __ldivmod (long num, long den, long *rem)
+{
+  long q, r;
+  __asm__ ("cltd; idivl %2"
+           : "=a" (q), "=&d" (r)
+           : "r?m" (den), "a" (num));
+  *rem = r;
+  return q;
+}
+
+static __inline__ unsigned long __uldivmod (unsigned long num,
+  unsigned long den, unsigned long *rem)
+{
+  unsigned long q, r;
+  __asm__ ("xorl %%edx,%%edx; divl %2"
+           : "=a" (q), "=&d" (r)
+           : "r?m" (den), "a" (num));
+  *rem = r;
+  return q;
+}
+
+/*
+    Divide a 64-bit integer by a 32-bit one:
+
+    A*2^32 + B    A            B + (A mod 32)
+    ---------- = --- * 2^32 + ----------------
+        C         C                  C
+*/
+static __inline__ long long __lldivmod (long long num, long den, long *rem)
+{
+  long long q;
+  long r;
+  __asm__ ("    movl    %%eax,%%esi;"
+           "    movl    %%edx,%%eax;"
+           "    pushl   %%edx;"
+           "    cltd;"
+           "    idivl   %2;"
+           "    ;"
+/* Now ensure remainder is smallest of possible two values (negative and
+   positive). For this we compare the remainder with positive and negative
+   denominator/2; if it is smaller than one and bigger than another we
+   consider it optimal, otherwise it can be made smaller by adding or
+   subtracting denominator to it. This is done to ensure no overflow
+   will occur at next division. */
+           "    movl    %2,%%ecx;"
+           "    sarl    $1,%%ecx;"      /* ecx = den/2 */
+           "    cmpl    %%ecx,%%edx;"
+           "    setl    %%bl;"
+           "    negl    %%ecx;"
+           "    cmpl    %%ecx,%%edx;"
+           "    setl    %%bh;"
+           "    xorb    %%bh,%%bl;"
+           "    jnz     1f;"            /* Remainder is between -den/2...den/2 */
+           "    ;"
+/* If remainder has same sign as denominator, we have to do r -= den; q++;
+   otherwise we have to do r += den; q--; */
+           "    movl    %2,%%ebx;"      /* ebx = den */
+           "    xorl    %%edx,%%ebx;"   /* r ^ den */
+           "    js      0f;"            /* Different signs */
+           "    subl    %2,%%edx;"      /* r -= den */
+           "    addl    $1,%%eax;"      /* q++ */
+           "    adcl    $0,%%edx;"
+           "    jmp     1f;"
+           "    ;"
+           "0:  addl    %2,%%edx;"      /* r += den */
+           "    subl    $1,%%eax;"      /* q-- */
+           "    sbbl    $0,%%edx;"
+           "    ;"
+           "1:  xchgl   %%eax,%%esi;"
+           "    idivl   %2;"
+           "    ;"
+           "    movl    %%edx,%1;"
+           "    cltd;"
+           "    addl    %%esi,%%edx;"
+           "    ;"
+/* Check if numerator has the same sign as remainder; if they have different
+   sign we should make the remainder have same sign as numerator to comply
+   with ANSI standard, which says we always should truncate the quotient
+   towards zero. */
+           "    popl    %%ebx;"         /* ebx = num >> 32 */
+           "    xorl    %1,%%ebx;"      /* sign(r) ^ sign(num) */
+           "    jns     3f;"            /* jump if same sign */
+           "    ;"
+/* If remainder has same sign as denominator, we have to do r -= den; q++;
+   otherwise we have to do r += den; q--; */
+           "    movl    %2,%%ebx;"
+           "    xorl    %1,%%ebx;"      /* r ^ den */
+           "    js      2f;"            /* Different signs */
+           "    subl    %2,%1;"         /* r -= den */
+           "    addl    $1,%%eax;"      /* q++ */
+           "    adcl    $0,%%edx;"
+           "    jmp     3f;"
+           "    ;"
+           "2:  addl    %2,%1;"         /* r += den */
+           "    subl    $1,%%eax;"      /* q-- */
+           "    sbbl    $0,%%edx;"
+           "    ;"
+           "3:  ;"
+           : "=A" (q), "=&c" (r)
+           : "r" (den), "A" (num)
+           : "ebx", "esi");
+  *rem = r;
+  return q;
+}
+
+/*
+    Same as __lldivmod except that if A < C, we can do just one division
+    instead of two because the result is always a 32-bit integer.
+*/
+static __inline__ unsigned long long __ulldivmod (unsigned long long num,
+  unsigned long den, unsigned long *rem)
+{
+  unsigned long long q;
+  unsigned long r;
+  __asm__ ("    movl    %%eax,%1;"
+           "    movl    %%edx,%%eax;"
+           "    xorl    %%edx,%%edx;"
+           "    divl    %2;"
+           "    xchgl   %%eax,%%ecx;"
+           "    divl    %2;"
+           "    xchgl   %%edx,%1;"
+           : "=A" (q), "=c" (r)
+           : "r?m" (den), "A" (num));
+  *rem = r;
+  return q;
+}
+
 #if defined (__cplusplus)
 }