code: plan9front

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vmx: avoid strdup() register names for register cache

If we tokenize the register file contents in a static buffer,
we can avoid having to duplicate the register names.

All callers to rpoke() provide constant register arguments
so they also do not need to be duplicated.

--- a/sys/src/cmd/vmx/vmx.c

+++ b/sys/src/cmd/vmx/vmx.c

@@ -106,9 +106,9 @@

 }

 enum { RCENT = 256 };

-char *rcname[RCENT];

-uvlong rcval[RCENT];

-uvlong rcvalid[(RCENT+63)/64], rcdirty[(RCENT+63)/64];

+static char *rcname[RCENT];

+static uvlong rcval[RCENT];

+static uvlong rcvalid[(RCENT+63)/64], rcdirty[(RCENT+63)/64];

 static int

 rclookup(char *n)

@@ -149,7 +149,7 @@

 static void

 rcload(void)

 {

-	char buf[4096];

+	static char buf[4096];

 	char *p, *q, *f[2];

 	int nf;

 	int i, rc;

@@ -166,14 +166,12 @@

 		nf = tokenize(p, f, nelem(f));

 		p = q + 1;

 		if(nf < 2) break;

-		free(rcname[i]);

-		rcname[i] = strdup(f[0]);

+		rcname[i] = f[0];

 		rcval[i] = strtoull(f[1], nil, 0);

 		rcvalid[i>>6] |= 1ULL<<(i&63);

 	}

 	for(; i < nelem(rcname); i++){

-		free(rcname[i]);

-		rcname[i] = 0;

+		rcname[i] = nil;

 		rcvalid[i>>6] &= ~(1ULL<<(i&63));

 	}

 }

@@ -204,7 +202,7 @@

 	}

 	for(i = 0; i < nelem(rcname); i++)

 		if(rcname[i] == nil){

-			rcname[i] = strdup(reg);

+			rcname[i] = reg;

 			break;

 		}

 	assert(i < nelem(rcname));