From 89d8b3efcfde4f676e1e0ba964851050c8aaba13 Mon Sep 17 00:00:00 2001
From: Kelvin Sherlock <ksherlock@gmail.com>
Date: Fri, 5 Apr 2019 18:43:54 -0400
Subject: [PATCH] disassembler - inline debug name support.

See IIgs technote #103.
---
 src/debug_shell.re2c | 125 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 124 insertions(+), 1 deletion(-)

diff --git a/src/debug_shell.re2c b/src/debug_shell.re2c
index 72f41b5..469b53d 100644
--- a/src/debug_shell.re2c
+++ b/src/debug_shell.re2c
@@ -426,6 +426,63 @@ static int is_jsr_bf00(word32 address) {
 
 static int g_disasm_psr;
 
+static const char *get_inline_debug_name(word32 address) {
+	static char buffer[256];
+
+	/* see IIgs technote #103 */
+	/* 82 xx xx brl pastname
+	   71 77
+	   name
+	   pastname:
+	 */
+
+	/* uthernet uses bra ... tsk tsk. */
+
+	int match = 0;
+	int offset = 0;
+
+	unsigned op = get_memory_c(address, 0);
+	if (op == 0x82
+		&& get_memory_c(address + 3, 0) == 0x71
+		&& get_memory_c(address + 4, 0) == 0x77) {
+		match = 1;
+		address += 5;
+
+		offset = 3 + (int16_t)get_memory16_c(address + 1, 0);
+		offset &= 0xffff;
+	}
+
+	if (op == 0x80
+		&& get_memory_c(address + 2, 0) == 0x71
+		&& get_memory_c(address + 3, 0) == 0x77) {
+		match = 1;
+		address += 4;
+
+		offset = 2 + (int8_t)get_memory_c(address + 1, 0);
+		offset &= 0xffff;
+
+	}
+
+
+	if (match) {
+		unsigned i, n;
+
+		/* sanity check it offset */
+
+		n = get_memory_c(address++, 0);
+		for (i = 0; i < n; ++i) {
+			unsigned char c = get_memory_c(address++, 0);
+			if (c & 0x80) return NULL;
+			if (!isprint(c)) return NULL;
+			buffer[i] = c;
+		}
+		buffer[i] = 0;
+		return buffer;
+	}
+
+	return NULL;
+}
+
 word32 do_list(word32 address, int lines) {
 
 	unsigned char buffer2[32];
@@ -578,7 +635,7 @@ word32 do_list(word32 address, int lines) {
 				comment = debug_tool_name(pc & 0xffff, bank);
 		}
 
-
+		uint32_t ea = 0;
 		switch (opcode) {
 			case 0xe2: /* sep */
 				g_disasm_psr|= operand;
@@ -602,6 +659,7 @@ word32 do_list(word32 address, int lines) {
 					}
 				}
 				break;
+#if 0
 			case 0xae: /* ldx ... */
 			case 0xbe:
 			case 0xa6:
@@ -613,6 +671,7 @@ word32 do_list(word32 address, int lines) {
 			case 0xca: /* dex */
 			case 0xe8: /* inx */
 				break;
+#endif
 			case 0x22: /* jsl */
 				if (operand == 0xe100a8) {
 					/* inline GS/OS call? */
@@ -628,6 +687,8 @@ word32 do_list(word32 address, int lines) {
 							buffer2[bsize++] = get_memory_c(address++, 0);
 						}
 					}
+				} else {
+					ea = operand;
 				}
 				break;
 			case 0x20: /* jsr */
@@ -643,8 +704,70 @@ word32 do_list(word32 address, int lines) {
 							buffer2[bsize++] = get_memory_c(address++, 0);
 						}
 					}
+				} else {
+					ea = (operand | (address & 0xff0000));
 				}
 				break;
+			case 0x82: {
+				ea = address + (int16_t)operand;
+				ea &= 0xffff;
+				ea |= pc & 0xff0000;
+
+				const char *name = get_inline_debug_name(pc);
+				/* start of an inline debug name? */
+				if (name) {
+					opcode_string = name;
+					buffer[0] = 0;
+
+					/* include the 0x77 71 magic bytes */
+					for (i = 0; i < 2; ++i) {
+						buffer2[bsize++] = get_memory_c(address++, 0);
+					}
+					address = ea;
+					ea = 0;
+				}
+				break;
+			}
+			case 0x80: {
+				ea = address + (int8_t)operand;
+				ea &= 0xffff;
+				ea |= pc & 0xff0000;
+
+				const char *name = get_inline_debug_name(pc);
+				/* start of an inline debug name? */
+				if (name) {
+					opcode_string = name;
+					buffer[0] = 0;
+
+					/* include the 0x77 71 magic bytes */
+					for (i = 0; i < 2; ++i) {
+						buffer2[bsize++] = get_memory_c(address++, 0);
+					}
+					address = ea;
+					ea = 0;
+				}
+				break;
+			}
+
+
+			case 0x10:
+			case 0x30:
+			case 0x50:
+			case 0x70:
+			case 0x90:
+			case 0xb0:
+			case 0xd0:
+			case 0xf0: {
+				ea = address + (int8_t)operand;
+				ea &= 0xffff;
+				ea |= pc & 0xff0000;
+				break;
+			}
+
+		}
+
+		if (ea && !comment) {
+			comment = get_inline_debug_name(ea);
 		}
 
 		n = printf("%02x/%04x: %s %s",