1 files changed, 49 insertions, 0 deletions
diff --git a/cmd/sbc_harness/ihex.h b/cmd/sbc_harness/ihex.h
new file mode 100644
index 0000000..35a3cbe
--- /dev/null
+++ b/cmd/sbc_harness/ihex.h
@@ -0,0 +1,49 @@
+/* sbc_harness/ihex.h - Intel Hex decoder
+ *
+ * Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+/* https://archive.org/details/IntelHEXStandard */
+
+#ifndef _SBC_HARNESS_IHEX_H_
+#define _SBC_HARNESS_IHEX_H_
+
+#include <stdbool.h> /* for bool */
+#include <stddef.h>  /* for size_t */
+#include <stdint.h>  /* for uint{n}_t */
+
+#include <libhw/generic/io.h>
+#include <libmisc/private.h>
+
+struct ihex_decoder {
+	void    *handle_arg;
+	error   (*handle_data)(void *arg, uint32_t off, uint8_t count, uint8_t *dat);
+	error   (*handle_set_exec_start_seg)(void *arg, uint16_t cs, uint16_t ip);
+	error   (*handle_set_exec_start_lin)(void *arg, uint32_t eip);
+	error   (*handle_eof)(void *arg);
+
+	BEGIN_PRIVATE(IHEX_H);
+
+	bool     seen_eof;
+	error    sticky_err;
+
+	/* ihex_decoder_write: deal with ASCII soup */
+	bool     in_record;
+	char     buf_char; /* the first nibble of a byte (still in ASCII) */
+
+	/* ihex_decode_byte: build records from decoded bytes  */
+	/* The currently-being-decoded record, after hex decoding.  */
+	uint16_t buf_len;
+	uint8_t  buf[0xFF+5];
+
+	/* ihex_handle_record: handle record semantics */
+	enum { _IHEX_MODE_NONE, _IHEX_MODE_SEG, _IHEX_MODE_LIN }        addr_mode;
+	uint32_t                                                        addr_base;
+
+	END_PRIVATE(IHEX_H);
+};
+LO_IMPLEMENTATION_H(io_writer, struct ihex_decoder, ihex_decoder);
+LO_IMPLEMENTATION_H(io_closer, struct ihex_decoder, ihex_decoder);
+
+#endif /* _SBC_HARNESS_IHEX_H_ */