Initial import

5 files changed, 227 insertions, 0 deletions

diff --git a/firmware/makehex.py b/firmware/makehex.py
new file mode 100644
index 0000000..a5ae740
--- /dev/null
+++ b/firmware/makehex.py
@@ -0,0 +1,17 @@
+#!/usr/bin/python3
+
+from sys import argv
+
+with open(argv[1], "rb") as f:
+    bindata = f.read()
+
+assert len(bindata) < 60*1024
+assert len(bindata) % 4 == 0
+
+for i in range(64*1024//4):
+    if i < len(bindata) // 4:
+        w = bindata[4*i : 4*i+4]
+        print("%02x%02x%02x%02x" % (w[3], w[2], w[1], w[0]))
+    else:
+        print("0")
+
diff --git a/firmware/sections.lds b/firmware/sections.lds
new file mode 100644
index 0000000..5e6e40c
--- /dev/null
+++ b/firmware/sections.lds
@@ -0,0 +1,9 @@
+SECTIONS {
+	.memory : {
+		. = 0x000000;
+		start*(.text);
+		*(.text);
+		*(*);
+		end = .;
+	}
+}
diff --git a/firmware/sieve.c b/firmware/sieve.c
new file mode 100644
index 0000000..c3372f4
--- /dev/null
+++ b/firmware/sieve.c
@@ -0,0 +1,78 @@
+// A simple Sieve of Eratosthenes
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#define BITMAP_SIZE 64
+#define OUTPORT 0x10000000
+
+static uint32_t bitmap[BITMAP_SIZE/32];
+
+static void bitmap_set(int idx)
+{
+	bitmap[idx/32] |= 1 << (idx % 32);
+}
+
+static bool bitmap_get(int idx)
+{
+	return (bitmap[idx/32] & (1 << (idx % 32))) != 0;
+}
+
+static void print_str(const char *p)
+{
+	while (*p != 0)
+		*((volatile uint32_t*)OUTPORT) = *(p++);
+}
+
+static void print_dec(int val)
+{
+	char buffer[10];
+	char *p = buffer;
+	while (val) {
+		*(p++) = val % 10;
+		val = val / 10;
+	}
+	while (p != buffer) {
+		*((volatile uint32_t*)OUTPORT) = '0' + *(--p);
+	}
+}
+
+static void print_prime(int idx, int val)
+{
+	if (idx < 10)
+		print_str(" ");
+	print_dec(idx);
+	if (idx / 10 == 1)
+		goto force_th;
+	switch (idx % 10) {
+		case 1: print_str("st"); break;
+		case 2: print_str("nd"); break;
+		case 3: print_str("rd"); break;
+	force_th:
+		default: print_str("th"); break;
+	}
+	print_str(" prime is ");
+	print_dec(val);
+	print_str(".\n");
+}
+
+void sieve()
+{
+	int i, j, k;
+	int idx = 1;
+	print_prime(idx++, 2);
+	for (i = 0; i < BITMAP_SIZE; i++) {
+		if (bitmap_get(i))
+			continue;
+		print_prime(idx++, 3+2*i);
+		for (j = 2*(3+2*i);; j += 3+2*i) {
+			if (j%2 == 0)
+				continue;
+			k = (j-3)/2;
+			if (k >= BITMAP_SIZE)
+				break;
+			bitmap_set(k);
+		}
+	}
+}
+
diff --git a/firmware/start.S b/firmware/start.S
new file mode 100644
index 0000000..34e44d8
--- /dev/null
+++ b/firmware/start.S
@@ -0,0 +1,80 @@
+	.section .text
+	.global start
+	.global sieve
+	.global stats
+
+#define TEST(n) \
+	.global n; .global n ## _ret; \
+	jal zero,n; n ## _ret:
+
+start:
+	TEST(lui)
+	TEST(auipc)
+	TEST(j)
+	TEST(jal)
+	TEST(jalr)
+
+	TEST(beq)
+	TEST(bne)
+	TEST(blt)
+	TEST(bge)
+	TEST(bltu)
+	TEST(bgeu)
+
+	TEST(lb)
+	TEST(lh)
+	TEST(lw)
+	TEST(lbu)
+	TEST(lhu)
+
+	TEST(sb)
+	TEST(sh)
+	TEST(sw)
+
+	TEST(addi)
+	TEST(slti) // also tests sltiu
+	TEST(xori)
+	TEST(ori)
+	TEST(andi)
+	TEST(slli)
+	TEST(srli)
+	TEST(srai)
+
+	TEST(add)
+	TEST(sub)
+	TEST(sll)
+	TEST(slt) // what is with sltu ?
+	TEST(xor)
+	TEST(srl)
+	TEST(sra)
+	TEST(or)
+	TEST(and)
+
+	TEST(fence_i)
+	TEST(simple)
+
+	/* set stack pointer */
+	lui sp,(64*1024)>>12
+
+	/* jump to sieve C code */
+	jal ra,sieve
+
+	/* jump to stats C code */
+	jal ra,stats
+
+	/* print "DONE\n" */
+	lui a0,0x10000000>>12
+	addi a1,zero,'D'
+	addi a2,zero,'O'
+	addi a3,zero,'N'
+	addi a4,zero,'E'
+	addi a5,zero,'\n'
+	sw a1,0(a0)
+	sw a2,0(a0)
+	sw a3,0(a0)
+	sw a4,0(a0)
+	sw a5,0(a0)
+
+	/* break */
+	sbreak
+
diff --git a/firmware/stats.c b/firmware/stats.c
new file mode 100644
index 0000000..c7b1b8e
--- /dev/null
+++ b/firmware/stats.c
@@ -0,0 +1,43 @@
+#include <stdint.h>
+#include <stdbool.h>
+#define OUTPORT 0x10000000
+
+static void print_str(const char *p)
+{
+	while (*p != 0)
+		*((volatile uint32_t*)OUTPORT) = *(p++);
+}
+
+static void print_dec(int val, int digits, bool zero_pad)
+{
+	char buffer[32];
+	char *p = buffer;
+	while (val || digits > 0) {
+		if (val)
+			*(p++) = '0' + val % 10;
+		else
+			*(p++) = zero_pad ? '0' : ' ';
+		val = val / 10;
+		digits--;
+	}
+	while (p != buffer) {
+		if (p[-1] == ' ' && p[-2] == ' ') p[-1] = '.';
+		*((volatile uint32_t*)OUTPORT) = *(--p);
+	}
+}
+
+void stats()
+{
+	int num_cycles, num_instr;
+	asm("rdcycle %0; rdinstret %1;" : "=r"(num_cycles), "=r"(num_instr));
+	print_str("Cycle counter ........");
+	print_dec(num_cycles, 8, false);
+	print_str("\nInstruction counter ..");
+	print_dec(num_instr, 8, false);
+	print_str("\nCPI: ");
+	print_dec((num_cycles / num_instr), 0, false);
+	print_str(".");
+	print_dec(((100 * num_cycles) / num_instr) % 100, 2, true);
+	print_str("\n");
+}
+