From 3967fccab7a41f8218b7ba589eee470d7ab4972a Mon Sep 17 00:00:00 2001
From: lemon <lsof@mailbox.org>
Date: Sun, 15 Jun 2025 16:18:58 +0200
Subject: maths

---
 Makefile |  2 +-
 pez.c    | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 1cc019b..4677bc2 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ opt: CFLAGS += -Oz
 opt: pez
 
 pez: repl.c pez.c pez.h
-	$(CC) -o$@ -lreadline $(CFLAGS) repl.c pez.c
+	$(CC) -o$@ -lm -lreadline $(CFLAGS) repl.c pez.c
 
 clean:
 	$(RM) pez
diff --git a/pez.c b/pez.c
index 3f64b28..e12ad46 100644
--- a/pez.c
+++ b/pez.c
@@ -9,6 +9,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <math.h>
 
 #ifdef __GNUC__
 #define FORCEINLINE __attribute__((always_inline))
@@ -2406,6 +2407,63 @@ f_ioclose(PezContext *cx, int argc)
     return 1;
 }
 
+static bool
+f_abs(PezContext *cx, int argc)
+{
+    PezNumber n;
+    TRY(pez_checksig(cx, argc, "abs", "number"));
+    pez_getnumber(cx, &n, -1);
+    return pez_pushnumber(cx, n < 0 ? -n : n);
+}
+
+static bool
+f_sqrt(PezContext *cx, int argc)
+{
+    PezNumber n;
+    TRY(pez_checksig(cx, argc, "sqrt", "number"));
+    pez_getnumber(cx, &n, -1);
+    return pez_pushnumber(cx, pez_ftonum(sqrtf(pez_numtof(n))));
+}
+
+static PezNumber
+xsin(PezNumber x)
+{
+    static uint16_t lut[4096];
+    PezNumber t;
+    bool neg;
+
+    if (!lut[8]) {
+        for (int i = 0; i <= 0xFFF; ++i) {
+            double f = (double)i * M_PI / 0x1000;
+            lut[i] = sin(f) * 0x1000;
+        }
+    }
+    if ((neg = x < 0)) x = -x;
+    t = lut[x&0xFFF];
+    if (x % FX(2) > FX(1)) t = -t;
+    return neg ? -t : t;
+}
+
+static bool
+f_xsin(PezContext *cx, int argc)
+{
+
+    PezNumber n;
+    TRY(pez_checksig(cx, argc, "xsin", "number"));
+    pez_getnumber(cx, &n, -1);
+    return pez_pushnumber(cx, xsin(n));
+}
+
+static bool
+f_xcos(PezContext *cx, int argc)
+{
+
+    PezNumber n;
+    TRY(pez_checksig(cx, argc, "xcos", "number"));
+    pez_getnumber(cx, &n, -1);
+    return pez_pushnumber(cx, xsin(n + 0x800));
+}
+
 static const struct coredef { const char *n; PezCFn *f; } core[] = {
     { "printf", f_printf },
     { "sprintf", f_sprintf },
@@ -2419,6 +2477,10 @@ static const struct coredef { const char *n; PezCFn *f; } core[] = {
     { "io#read", f_ioread },
     { "io#write", f_iowrite },
     { "io#close", f_ioclose },
+    { "abs", f_abs },
+    { "sqrt", f_sqrt },
+    { "xsin", f_xsin },
+    { "xcos", f_xcos },
 };
 
 static bool
-- 
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