Checkin: various small changes

4 files changed, 103 insertions, 15 deletions

diff --git a/sys/libn/genutf8.py b/sys/libn/genutf8.py
index f4b9f8c..9ce9975 100755
--- a/sys/libn/genutf8.py
+++ b/sys/libn/genutf8.py
@@ -77,7 +77,6 @@ def puttab(s, fd, name):
 RUNEMAX = 0x10FFFF
 
 if __name__ == "__main__":
-
     alphas  = set()
     lowers  = set()
     uppers  = set()
diff --git a/sys/libn/memory.c b/sys/libn/memory.c
index 795fe1f..a749e4c 100644
--- a/sys/libn/memory.c
+++ b/sys/libn/memory.c
@@ -3,25 +3,25 @@
 
 static
 void
-·free(void* _, void* ptr) {
+·free(void *_, void *ptr) {
     return free(ptr);
 }
 
 static
 void *
-·alloc(void* _, uint n, ulong size) {
+·alloc(void *_, uint n, ulong size) {
     return malloc(n*size);
 }
 
 static
 void *
-·calloc(void* _, uint n, ulong size) {
+·calloc(void *_, uint n, ulong size) {
     return calloc(n, size);
 }
 
 static 
 void *
-·realloc(void* _, void *ptr, uint n, ulong size) {
+·realloc(void *_, void *ptr, uint n, ulong size) {
     return realloc(ptr, n*size);
 }
 
@@ -89,7 +89,7 @@ void
 #define ALIGN_DOWN_PTR(p, a) ((void*)ALIGN_DOWN((uintptr)(p), (a)))
 #define ALIGN_UP_PTR(p, a) ((void*)ALIGN_UP((uintptr)(p), (a)))
 
-struct Block 
+struct Block
 {
     struct Block *next;
     byte   buf[];
@@ -97,8 +97,8 @@ struct Block
 
 struct mem·Arena
 {
-    mem·Allocator heap;
-    void  *impl;
+    void  *heap;
+    mem·Allocator mem;
 
     byte  *off;
     byte  *end;
@@ -110,8 +110,8 @@ mem·Arena*
 mem·makearena(mem·Allocator from, void *impl)
 {
     mem·Arena *a  = from.alloc(impl, 1, sizeof(*a) + ARENA_BLOCK_SIZE);
-    a->impl       = impl;
-    a->heap       = from;
+    a->mem        = from;
+    a->heap       = impl;
     a->off        = a->first.buf;
     a->end        = a->first.buf + ARENA_BLOCK_SIZE;
     a->curr       = &a->first;
@@ -128,7 +128,7 @@ grow(mem·Arena *a, vlong min)
     struct Block *blk;
 
     size   = ALIGN_UP(MAX(min, ARENA_BLOCK_SIZE), ARENA_ALIGN);
-    blk    = a->heap.alloc(a->impl, 1, sizeof(*blk) + size);
+    blk    = a->mem.alloc(a->heap, 1, sizeof(*blk) + size);
     a->off = blk->buf;
     a->end = a->off + size;
 
@@ -142,7 +142,7 @@ grow(mem·Arena *a, vlong min)
 void*
 mem·arenaalloc(mem·Arena *a, uint n, ulong size)
 {
-    if (!n) {
+    if(!n) {
         return nil;
     }
 
@@ -172,13 +172,32 @@ mem·freearena(mem·Arena *a)
     it = a->first.next;
     while (it != nil) {
         next = it->next;
-        a->heap.free(a->impl, it);
+        a->mem.free(a->heap, it);
         it   = next;
     }
 
-    a->heap.free(a->impl, a);
+    a->mem.free(a->heap, a);
 }
 
+static
+void*
+·arenaalloc(void *heap, uint n, ulong size)
+{
+    return mem·arenaalloc(heap, n, size);
+}
+
+static
+void
+·arenafree(void *heap, void *ptr)
+{
+    /* no-op */
+}
+
+mem·Allocator mem·ArenaAllocator = {
+    .alloc = ·arenaalloc,
+    .free  = ·arenafree,
+};
+
 // -------------------------------------------------------------------------
 // Generalized memory helpers
 
diff --git a/sys/libn/random.c b/sys/libn/random.c
index 237127e..9e80b34 100644
--- a/sys/libn/random.c
+++ b/sys/libn/random.c
@@ -82,12 +82,82 @@ rng·exponential(double lambda)
     return -log(1 - f)/lambda;
 }
 
+static inline
+double
+erfinv(double x)
+{
+    /* useful constants */
+    static double
+      a0 = 1.1975323115670912564578e0, a1 = 4.7072688112383978012285e1,
+      a2 = 6.9706266534389598238465e2, a3 = 4.8548868893843886794648e3,
+      a4 = 1.6235862515167575384252e4, a5 = 2.3782041382114385731252e4,
+      a6 = 1.1819493347062294404278e4, a7 = 8.8709406962545514830200e2,
+
+      b0 = 1.0000000000000000000e0, b1 = 4.2313330701600911252e1,
+      b2 = 6.8718700749205790830e2, b3 = 5.3941960214247511077e3,
+      b4 = 2.1213794301586595867e4, b5 = 3.9307895800092710610e4,
+      b6 = 2.8729085735721942674e4, b7 = 5.2264952788528545610e3,
+
+      c0 = 1.42343711074968357734e0,  c1 = 4.63033784615654529590e0,
+      c2 = 5.76949722146069140550e0,  c3 = 3.64784832476320460504e0,
+      c4 = 1.27045825245236838258e0,  c5 = 2.41780725177450611770e-1,
+      c6 = 2.27238449892691845833e-2, c7 = 7.74545014278341407640e-4,
+
+      d0 = 1.4142135623730950488016887e0,  d1 = 2.9036514445419946173133295e0,
+      d2 = 2.3707661626024532365971225e0,  d3 = 9.7547832001787427186894837e-1,
+      d4 = 2.0945065210512749128288442e-1, d5 = 2.1494160384252876777097297e-2,
+      d6 = 7.7441459065157709165577218e-4, d7 = 1.4859850019840355905497876e-9,
+
+      e0 = 6.65790464350110377720e0,  e1 = 5.46378491116411436990e0,
+      e2 = 1.78482653991729133580e0,  e3 = 2.96560571828504891230e-1,
+      e4 = 2.65321895265761230930e-2, e5 = 1.24266094738807843860e-3,
+      e6 = 2.71155556874348757815e-5, e7 = 2.01033439929228813265e-7,
+
+      f0 = 1.414213562373095048801689e0,  f1 = 8.482908416595164588112026e-1,
+      f2 = 1.936480946950659106176712e-1, f3 = 2.103693768272068968719679e-2,
+      f4 = 1.112800997078859844711555e-3, f5 = 2.611088405080593625138020e-5,
+      f6 = 2.010321207683943062279931e-7, f7 = 2.891024605872965461538222e-15,
+
+      Ln2 = 0.693147180559945309417232121458176568075500134360255254120680009;
+
+    int s;
+    double r, z1, z2;
+
+    if(x < 0) {
+        s = -1;
+        x = -x;
+    } else {
+        s = +1;
+    }
+
+    if(x <= 0.85) {
+        r = 0.180625 - 0.25*x*x;
+        z1 = ((((((a7*r+a6)*r+a5)*r+a4)*r+a3)*r+a2)*r+a1)*r + a0;
+        z2 = ((((((b7*r+b6)*r+b5)*r+b4)*r+b3)*r+b2)*r+b1)*r + b0;
+        return s*(x*z1) / z2;
+    }
+    r = sqrt(Ln2 - log(1.0-x));
+    if(r <= 5.0) {
+        r -= 1.6;
+        z1 = ((((((c7*r+c6)*r+c5)*r+c4)*r+c3)*r+c2)*r+c1)*r + c0;
+        z2 = ((((((d7*r+d6)*r+d5)*r+d4)*r+d3)*r+d2)*r+d1)*r + d0;
+    } else {
+        r -= 5.0;
+        z1 = ((((((e7*r+e6)*r+e5)*r+e4)*r+e3)*r+e2)*r+e1)*r + e0;
+        z2 = ((((((f7*r+f6)*r+f5)*r+f4)*r+f3)*r+f2)*r+f1)*r + f0;
+    }
+
+    return s*z1/z2;
+}
+
+
 double
 rng·normal(void)
 {
     double f;
     f = rng·random();
 
+    return sqrt(2)*erfinv(2*f-1);
 }
 
 /* Returns true or false on success of trial */
diff --git a/sys/libn/rules.mk b/sys/libn/rules.mk
index d519b67..452587e 100644
--- a/sys/libn/rules.mk
+++ b/sys/libn/rules.mk
@@ -21,7 +21,7 @@ SRCS_$(d) := \
 	$(d)/string.c
 
 TSTS_$(d) := \
-	$(d)/test.c 
+	$(d)/test.c
 
 LIBS_$(d) := $(d)/libn.a
 BINS_$(d) :=