1 files changed, 151 insertions, 0 deletions
diff --git a/firmware/multest.c b/firmware/multest.c
new file mode 100644
index 0000000..1706400
--- /dev/null
+++ b/firmware/multest.c
@@ -0,0 +1,151 @@
+// This is free and unencumbered software released into the public domain.
+//
+// Anyone is free to copy, modify, publish, use, compile, sell, or
+// distribute this software, either in source code form or as a compiled
+// binary, for any purpose, commercial or non-commercial, and by any
+// means.
+
+#include "firmware.h"
+
+static uint32_t xorshift32(void) {
+	static uint32_t x = 314159265;
+	x ^= x << 13;
+	x ^= x >> 17;
+	x ^= x << 5;
+	return x;
+}
+
+void multest(void)
+{
+	for (int i = 0; i < 15; i++)
+	{
+		uint32_t a = xorshift32();
+		uint32_t b = xorshift32();
+
+		switch (i)
+		{
+		case 0:
+			a = 0x80000000;
+			b = 0xFFFFFFFF;
+			break;
+		case 1:
+			a = 0;
+			b = 0;
+			break;
+		case 2:
+			a |= 0x80000000;
+			b = 0;
+			break;
+		case 3:
+			a &= 0x7FFFFFFF;
+			b = 0;
+			break;
+		}
+
+		uint64_t au = a, bu = b;
+		int64_t as = (int32_t)a, bs = (int32_t)b;
+
+		print_str("input     [");
+		print_hex(as >> 32, 8);
+		print_str("] ");
+		print_hex(a, 8);
+		print_str(" [");
+		print_hex(bs >> 32, 8);
+		print_str("] ");
+		print_hex(b, 8);
+		print_chr('\n');
+
+		uint32_t h_mul, h_mulh, h_mulhsu, h_mulhu;
+		print_str("hard mul   ");
+
+		h_mul = hard_mul(a, b);
+		print_hex(h_mul, 8);
+		print_str("  ");
+
+		h_mulh = hard_mulh(a, b);
+		print_hex(h_mulh, 8);
+		print_str("  ");
+
+		h_mulhsu = hard_mulhsu(a, b);
+		print_hex(h_mulhsu, 8);
+		print_str("  ");
+
+		h_mulhu = hard_mulhu(a, b);
+		print_hex(h_mulhu, 8);
+		print_chr('\n');
+
+		uint32_t s_mul, s_mulh, s_mulhsu, s_mulhu;
+		print_str("soft mul   ");
+
+		s_mul = a * b;
+		print_hex(s_mul, 8);
+		print_str("  ");
+
+		s_mulh = (as * bs) >> 32;
+		print_hex(s_mulh, 8);
+		print_str("  ");
+
+		s_mulhsu = (as * bu) >> 32;
+		print_hex(s_mulhsu, 8);
+		print_str("  ");
+
+		s_mulhu = (au * bu) >> 32;
+		print_hex(s_mulhu, 8);
+		print_str("  ");
+
+		if (s_mul != h_mul || s_mulh != h_mulh || s_mulhsu != h_mulhsu || s_mulhu != h_mulhu) {
+			print_str("ERROR!\n");
+			__asm__ volatile ("ebreak");
+			return;
+		}
+
+		print_str(" OK\n");
+
+		uint32_t h_div, h_divu, h_rem, h_remu;
+		print_str("hard div   ");
+
+		h_div = hard_div(a, b);
+		print_hex(h_div, 8);
+		print_str("  ");
+
+		h_divu = hard_divu(a, b);
+		print_hex(h_divu, 8);
+		print_str("  ");
+
+		h_rem = hard_rem(a, b);
+		print_hex(h_rem, 8);
+		print_str("  ");
+
+		h_remu = hard_remu(a, b);
+		print_hex(h_remu, 8);
+		print_chr('\n');
+
+		uint32_t s_div, s_divu, s_rem, s_remu;
+		print_str("soft div   ");
+
+		s_div = b ? as / bs : 0xffffffff;
+		print_hex(s_div, 8);
+		print_str("  ");
+
+		s_divu = b ? au / bu : 0xffffffff;
+		print_hex(s_divu, 8);
+		print_str("  ");
+
+		s_rem = b ? as % bs : a;
+		print_hex(s_rem, 8);
+		print_str("  ");
+
+		s_remu = b ? au % bu : a;
+		print_hex(s_remu, 8);
+		print_str("  ");
+
+		if (s_div != h_div || s_divu != h_divu || s_rem != h_rem || s_remu != h_remu) {
+			print_str("ERROR!\n");
+			__asm__ volatile ("ebreak");
+			return;
+		}
+
+		print_str(" OK\n");
+	}
+}
+