Rename _bsr/_bsf to bsr/bsf

Now that these functions are behind _COSMO_SOURCE there's no reason for
having the ugly underscore anymore. To use these functions, you need to
pass -mcosmo to cosmocc.

third_party/chibicc/as.c

@@ -2028,7 +2028,7 @@ static int ParseModrm(struct As *a, int *disp) {
         if (((reg & 070) >> 3) == 2) modrm |= HASASZ;  // asz
         if (IsComma(a)) {
           ++a->i;
-          modrm |= (_bsr(GetInt(a)) & 3) << 6;
+          modrm |= (bsr(GetInt(a)) & 3) << 6;
         }
       }
       ConsumePunct(a, ')');

third_party/chibicc/asm.c

@@ -301,7 +301,7 @@ static void PickAsmRegisters(Asm *a) {
           if (!(m = a->ops[i].regmask)) break;
           if (popcnt(m) != j) break;
           if (!(m &= regset)) CouldNotAllocateRegister(&a->ops[i], "rm");
-          pick = 1 << (a->ops[i].reg = _bsf(m));
+          pick = 1 << (a->ops[i].reg = bsf(m));
           if (pick & PRECIOUS) a->regclob |= pick;
           regset &= ~pick;
           a->ops[i].regmask = 0;
@@ -309,14 +309,14 @@ static void PickAsmRegisters(Asm *a) {
         case kAsmXmm:
           if (!(m = a->ops[i].regmask)) break;
           if (!(m &= xmmset)) CouldNotAllocateRegister(&a->ops[i], "xmm");
-          xmmset &= ~(1 << (a->ops[i].reg = _bsf(m)));
+          xmmset &= ~(1 << (a->ops[i].reg = bsf(m)));
           a->ops[i].regmask = 0;
           break;
         case kAsmFpu:
           if (!(m = a->ops[i].x87mask)) break;
           if (popcnt(m) != j) break;
           if (!(m &= x87sts)) CouldNotAllocateRegister(&a->ops[i], "fpu");
-          x87sts &= ~(1 << (a->ops[i].reg = _bsf(m)));
+          x87sts &= ~(1 << (a->ops[i].reg = bsf(m)));
           a->ops[i].x87mask = 0;
           break;
         default:
@@ -540,7 +540,7 @@ static char *HandleAsmSpecifier(Asm *a, char *p) {
   if ((i = c - '0') >= a->n) {
     error_tok(a->tok, "bad asm reference at offset %d", p - a->str);
   }
-  z = _bsr(a->ops[i].node->ty->size);
+  z = bsr(a->ops[i].node->ty->size);
   if (z > 3 && a->ops[i].type == kAsmReg) {
     error_tok(a->tok, "bad asm op size");
   }
@@ -679,7 +679,7 @@ static void StoreAsmOutputs(Asm *a) {
           println("\tset%s\t(%%rax)", a->ops[i].str + a->ops[i].predicate);
           break;
         case kAsmReg:
-          z = _bsr(a->ops[i].node->ty->size);
+          z = bsr(a->ops[i].node->ty->size);
           if (a->ops[i].reg) {
             gen_addr(a->ops[i].node);
             if (z > 3) error_tok(a->tok, "bad asm out size");
@@ -734,7 +734,7 @@ static void StoreAsmOutputs(Asm *a) {
 static void PushClobbers(Asm *a) {
   int i, regs = a->regclob & PRECIOUS;
   while (regs) {
-    i = _bsf(regs);
+    i = bsf(regs);
     pushreg(kGreg[3][i]);
     regs &= ~(1 << i);
   }
@@ -743,7 +743,7 @@ static void PushClobbers(Asm *a) {
 static void PopClobbers(Asm *a) {
   int i, regs = a->regclob & PRECIOUS;
   while (regs) {
-    i = _bsr(regs);
+    i = bsr(regs);
     popreg(kGreg[3][i]);
     regs &= ~(1 << i);
   }

third_party/chibicc/dox2.c

@@ -281,7 +281,7 @@ static int CompareDoxIndexEntry(const void *p1, const void *p2, void *arg) {
 }
 
 static unsigned long roundup2pow(unsigned long x) {
-  return x > 1 ? 2ul << _bsrl(x - 1) : x ? 1 : 0;
+  return x > 1 ? 2ul << bsrl(x - 1) : x ? 1 : 0;
 }
 
 static void IndexDox(struct Dox *dox) {

third_party/chibicc/file.c

@@ -67,7 +67,7 @@ void canonicalize_newline(char *p) {
           p += 16;
           q += 16;
         } else {
-          m = _bsf(m);
+          m = bsf(m);
           memmove(q, p, m);
           p += m;
           q += m;
@@ -126,7 +126,7 @@ void remove_backslash_newline(char *p) {
           i += 16;
           j += 16;
         } else {
-          m = _bsf(m);
+          m = bsf(m);
           memmove(p + j, p + i, m);
           i += m;
           j += m;

third_party/chibicc/test/implicit_test.c

@@ -9,7 +9,7 @@ implicit_functions_are_long() {
 }
 
 external_functions_are_long() {
-  if (_bsrl(0x0001000000000000) != 48) {
+  if (bsrl(0x0001000000000000) != 48) {
     __builtin_trap();
   }
 }

third_party/chibicc/tokenize.c

@@ -680,7 +680,7 @@ static void convert_universal_chars(char *p) {
           p += 16;
           q += 16;
         } else {
-          m = _bsf(m);
+          m = bsf(m);
           memmove(q, p, m);
           p += m;
           q += m;