altos: Add 64-bit add/mul/shift for SDCC

SDCC doeesn't provide a native 64-bit type (sigh), so
implement the minimal operations necessary for the MS5607 conversion
routine.

Signed-off-by: Keith Packard <keithp@keithp.com>

2 files changed, 158 insertions, 0 deletions

diff --git a/src/core/ao_int64.c b/src/core/ao_int64.c
new file mode 100644
index 00000000..1fe717dc
--- /dev/null
+++ b/src/core/ao_int64.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <ao_int64.h>
+
+void ao_plus64(ao_int64_t *r, ao_int64_t *a, ao_int64_t *b) {
+	uint32_t	t;
+
+	r->low = t = a->low + b->low;
+	r->high = a->high + b->high;
+	if (t < a->low)
+		r->high++;
+}
+
+void ao_rshift64(ao_int64_t *r, ao_int64_t *a, uint8_t d) {
+	if (d < 32) {
+		r->high = (int32_t) a->high >> d;
+		r->low = a->low >> d;
+		if (d)
+			r->low |= a->high << (32 - d);
+	} else {
+		d &= 0x1f;
+		r->high = 0;
+		r->low = (int32_t) a->high >> d;
+	}
+}
+
+void ao_lshift64(ao_int64_t *r, ao_int64_t *a, uint8_t d) {
+	if (d < 32) {
+		r->high = a->high << d;
+		r->low = a->low << d;
+		if (d)
+			r->high |= a->low >> (32 - d);
+	} else {
+		d &= 0x1f;
+		r->low = 0;
+		r->high = a->low << d;
+	}
+}
+
+void ao_umul64(ao_int64_t *r, uint32_t a, uint32_t b)
+{
+	uint32_t	r1;
+	uint32_t	r2, r3, r4;
+	ao_int64_t	s,t,u,v;
+	r1 = (uint32_t) (uint16_t) a * (uint16_t) b;
+	r2 = (uint32_t) (uint16_t) (a >> 16) * (uint16_t) b;
+	r3 = (uint32_t) (uint16_t) a * (uint16_t) (b >> 16);
+	r4 = (uint32_t) (uint16_t) (a >> 16) * (uint16_t) (b >> 16);
+
+	s.low = r1;
+	s.high = r4;
+
+	t.high = (uint32_t) r2 >> 16;
+	t.low = r2 << 16;
+	ao_plus64(&u, &s, &t);
+
+	v.high = (int32_t) r3 >> 16;
+	v.low = r3 << 16;
+	ao_plus64(r, &u, &v);
+}
+
+void ao_neg64(ao_int64_t *r, ao_int64_t *a) {
+	r->high = ~a->high;
+	r->low = ~a->low;
+	if (!++r->low)
+		r->high++;
+}
+
+void ao_mul64(ao_int64_t *r, int32_t a, int32_t b) {
+	uint8_t		negative = 0;
+
+	if (a < 0) {
+		a = -a;
+		negative = 1;
+	}
+	if (b < 0) {
+		b = -b;
+		negative = !negative;
+	}
+	ao_umul64(r, a, b);
+	if (negative)
+		ao_neg64(r, r);
+}
+
+void ao_umul64_16(ao_int64_t *r, ao_int64_t *a, uint16_t b) {
+	uint32_t	low = a->low;
+	ao_umul64(r, (uint32_t) low >> 1, (uint32_t) b << 1);
+	if (low & 1) {
+		if ((uint32_t) (r->low += b) < (uint32_t) b)
+			r->high++;
+	}
+	r->high += a->high * b;
+}
+
+void ao_mul64_16(ao_int64_t *r, ao_int64_t *a, uint16_t b) {
+	if ((int32_t) a->high < 0) {
+		ao_int64_t	t;
+
+		ao_neg64(&t, a);
+		ao_umul64_16(r, &t, b);
+		ao_neg64(r, r);
+	} else
+		ao_umul64_16(r, a, b);
+}
diff --git a/src/core/ao_int64.h b/src/core/ao_int64.h
new file mode 100644
index 00000000..93aa87e4
--- /dev/null
+++ b/src/core/ao_int64.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef _AO_INT64_H_
+#define _AO_INT64_H_
+
+#include <stdint.h>
+
+typedef struct {
+	uint32_t	high;
+	uint32_t	low;
+} ao_int64_t;
+
+void ao_plus64(ao_int64_t *r, ao_int64_t *a, ao_int64_t *b);
+void ao_rshift64(ao_int64_t *r, ao_int64_t *a, uint8_t d);
+void ao_lshift64(ao_int64_t *r, ao_int64_t *a, uint8_t d);
+void ao_mul64(ao_int64_t *r, int32_t a, int32_t b);
+void ao_mul64_16(ao_int64_t *r, ao_int64_t *a, uint16_t b);
+
+#define ao_int64_init32(r, a) (((r)->high = 0), (r)->low = (a))
+#define ao_int64_init64(r, a, b) (((r)->high = (a)), (r)->low = (b))
+
+#define ao_cast64(a) (((int64_t) (a)->high << 32) | (a)->low)
+
+#endif /* _AO_INT64_H_ */