From 8a8b59f19b434e3519502d5506d88046e645078f Mon Sep 17 00:00:00 2001
From: Raphael Assenat <raph@raphnet.net>
Date: Sat, 3 Oct 2015 12:00:31 -0400
Subject: [PATCH] Add .hex file loader

---
 tool/Makefile |   2 +-
 tool/ihex.c   | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tool/ihex.h   |   7 +++
 3 files changed, 137 insertions(+), 1 deletion(-)
 create mode 100644 tool/ihex.c
 create mode 100644 tool/ihex.h

diff --git a/tool/Makefile b/tool/Makefile
index 9b77c0d..c23f3c7 100644
--- a/tool/Makefile
+++ b/tool/Makefile
@@ -8,7 +8,7 @@ PREFIX=/usr/local
 
 PROG=gcn64ctl
 
-OBJS=main.o gcn64.o mempak.o gcn64lib.o hexdump.o gc2n64_adapter.o
+OBJS=main.o gcn64.o mempak.o gcn64lib.o hexdump.o gc2n64_adapter.o ihex.o
 
 .PHONY : clean install
 
diff --git a/tool/ihex.c b/tool/ihex.c
new file mode 100644
index 0000000..1422d5b
--- /dev/null
+++ b/tool/ihex.c
@@ -0,0 +1,129 @@
+#include <stdio.h>
+#include <string.h>
+#include "hexdump.h"
+
+static unsigned char chk(unsigned char *buf, int len)
+{
+	int i;
+	unsigned char r = 0;
+
+	for (i=0; i<len; i++) {
+		r += buf[i];
+	}
+	return r;
+}
+
+/* \return The highest address written to, or negative on errors.
+ */
+int load_ihex(const char *file, unsigned char *dstbuf, int bufsize)
+{
+	FILE *fptr;
+	char linebuf[550];
+	unsigned char databuf[2+1+255+1];
+	int ret = 0;
+	int line = 0;
+	int eof_seen = 0;
+	unsigned int max_address = 0;
+
+	fptr = fopen(file, "r");
+	if (!fptr) {
+		perror("fopen");
+		return -1;
+	}
+
+	do {
+		if (fgets(linebuf, sizeof(linebuf), fptr)) {
+			unsigned int data_count;
+			unsigned int address;
+			int input_nibbles, input_bytes;
+			int i;
+
+			line++;
+
+			if (linebuf[0] != ':') {
+				fprintf(stderr, "Ignored invalid line %d\n", line);
+				continue;
+			}
+
+			if (eof_seen) {
+				fprintf(stderr, "extra data after EOF record in hex file\n");
+				ret = -7;
+				goto err;
+			}
+
+			// :10 0000 00 92C064C7ABC0AAC0A9C0A8C0A7C0A6C0 00
+			//  ^  ^    ^  ^                                ^-- Checksum
+			//  |  |    |  +----- Data [data_count]
+			//  |  |    +---- Record type
+			//  |  +------ Address
+			//  +----- data_count
+			//
+
+			input_nibbles = strlen(linebuf) - 1;
+
+			for (input_bytes=0,i=0; i<input_nibbles; i+=2) {
+				unsigned int byte;
+				if (1 != sscanf(linebuf + 1 + i, "%02x", &byte)) {
+					break;
+				}
+				databuf[input_bytes] = byte;
+				input_bytes++;
+			}
+
+			//printf("Input bytes: %d\n", input_bytes);
+			//printHexBuf(databuf, input_bytes);
+
+			// Validate the record checksum
+			if (chk(databuf, input_bytes)) {
+				fprintf(stderr, "Bad checksum at line %d\n", line);
+				ret = -4;
+				goto err;
+			}
+
+			// Data length sanity check
+			data_count = databuf[0];
+			if (input_bytes != 1+2+1+data_count+1) {
+				fprintf(stderr, "Invalid record (less data than expected) at line %d\n", line);
+				ret = -5;
+				goto err;
+			}
+
+			address = databuf[1]<<8 | databuf[2];
+
+			switch(databuf[3])
+			{
+				case 0x00: // Data
+					if (address + data_count > bufsize) {
+						fprintf(stderr, "hex file too large\n");
+						ret = -6;
+						goto err;
+					}
+					if (address + data_count > max_address) {
+						max_address = address + data_count;
+					}
+					memcpy(dstbuf + address, databuf + 4, data_count);
+					break;
+
+				case 0x01: // EOF
+					eof_seen = 1;
+					break;
+
+				default:
+				case 0x02: // Extended segment address
+				case 0x03: // Start segment address
+				case 0x04: // Extended linear address
+				case 0x05: // Start linear address
+					fprintf(stderr, "ihex parser: Unimplemented record type 0x%02x\n", databuf[3]);
+					ret = -2;
+					goto err;
+			}
+
+		}
+	} while (!feof(fptr));
+
+	return max_address;
+
+err:
+	fclose(fptr);
+	return ret;
+}
diff --git a/tool/ihex.h b/tool/ihex.h
new file mode 100644
index 0000000..a55d5d6
--- /dev/null
+++ b/tool/ihex.h
@@ -0,0 +1,7 @@
+#ifndef _ihex_h__
+#define _ihex_h__
+
+int load_ihex(const char *file, unsigned char *dstbuf, int bufsize);
+
+#endif // _ihex_h__
+