Added Pico Co-Processor Interface (PCPI)

3 files changed, 110 insertions, 0 deletions

diff --git a/firmware/firmware.h b/firmware/firmware.h
index 7744463..b4fa4f8 100644
--- a/firmware/firmware.h
+++ b/firmware/firmware.h
@@ -16,6 +16,13 @@ void print_hex(unsigned int val);
 // sieve.c
 void sieve();
 
+// multest.c
+uint32_t hard_mul(uint32_t a, uint32_t b);
+uint32_t hard_mulh(uint32_t a, uint32_t b);
+uint32_t hard_mulhsu(uint32_t a, uint32_t b);
+uint32_t hard_mulhu(uint32_t a, uint32_t b);
+void multest();
+
 // stats.c
 void stats();
 
diff --git a/firmware/multest.c b/firmware/multest.c
new file mode 100644
index 0000000..3d41267
--- /dev/null
+++ b/firmware/multest.c
@@ -0,0 +1,79 @@
+#include "firmware.h"
+
+uint32_t xorshift32() {
+	static uint32_t x = 314159265;
+	x ^= x << 13;
+	x ^= x >> 17;
+	x ^= x << 5;
+	return x;
+}
+
+void multest()
+{
+	int i;
+	for (i = 0; i < 10; i++)
+	{
+		uint32_t a = xorshift32();
+		uint32_t b = xorshift32();
+
+		uint64_t au = a, bu = b;
+		int64_t as = (int32_t)a, bs = (int32_t)b;
+
+		print_str("input [");
+		print_hex(as >> 32);
+		print_str("] ");
+		print_hex(a);
+		print_str(" [");
+		print_hex(bs >> 32);
+		print_str("] ");
+		print_hex(b);
+		print_chr('\n');
+
+		uint32_t h_mul, h_mulh, h_mulhsu, h_mulhu;
+		print_str("hard   ");
+
+		h_mul = hard_mul(a, b);
+		print_hex(h_mul);
+		print_str("  ");
+
+		h_mulh = hard_mulh(a, b);
+		print_hex(h_mulh);
+		print_str("  ");
+
+		h_mulhsu = hard_mulhsu(a, b);
+		print_hex(h_mulhsu);
+		print_str("  ");
+
+		h_mulhu = hard_mulhu(a, b);
+		print_hex(h_mulhu);
+		print_chr('\n');
+
+		uint32_t s_mul, s_mulh, s_mulhsu, s_mulhu;
+		print_str("soft   ");
+
+		s_mul = a * b;
+		print_hex(s_mul);
+		print_str("  ");
+
+		s_mulh = (as * bs) >> 32;
+		print_hex(s_mulh);
+		print_str("  ");
+
+		s_mulhsu = (as * bu) >> 32;
+		print_hex(s_mulhsu);
+		print_str("  ");
+
+		s_mulhu = (au * bu) >> 32;
+		print_hex(s_mulhu);
+		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 ("sbreak");
+			return;
+		}
+
+		print_str(" OK\n");
+	}
+}
+
diff --git a/firmware/start.S b/firmware/start.S
index 990cf06..bf2a55e 100644
--- a/firmware/start.S
+++ b/firmware/start.S
@@ -1,6 +1,11 @@
 	.section .text
 	.global irq
 	.global sieve
+	.global multest
+	.global hard_mul
+	.global hard_mulh
+	.global hard_mulhsu
+	.global hard_mulhu
 	.global stats
 
 #define TEST(n) \
@@ -220,6 +225,9 @@ start:
 	/* jump to sieve C code */
 	jal ra,sieve
 
+	/* jump to sieve C code */
+	jal ra,multest
+
 	/* jump to stats C code */
 	jal ra,stats
 
@@ -239,3 +247,19 @@ start:
 	/* break */
 	sbreak
 
+hard_mul:
+	mul a0, a0, a1
+	ret
+
+hard_mulh:
+	mulh a0, a0, a1
+	ret
+
+hard_mulhsu:
+	mulhsu a0, a0, a1
+	ret
+
+hard_mulhu:
+	mulhu a0, a0, a1
+	ret
+