From 7d0d2b9ecddea35722fd1d09c99735b98f6f0362 Mon Sep 17 00:00:00 2001
From: Shamus Hammons <jlhamm@acm.org>
Date: Fri, 9 Aug 2019 09:12:14 -0500
Subject: [PATCH] Fix a few minor problems with 030 mode PC relative fixups.

---
 6502.c   |  2 +-
 eagen0.c | 38 +++++++++++++++++++++++++++++++-------
 object.c |  4 ++--
 sect.c   | 19 ++++++++++++++++++-
 sect.h   |  1 +
 5 files changed, 53 insertions(+), 11 deletions(-)

diff --git a/6502.c b/6502.c
index 4c188cf..ef95a0c 100644
--- a/6502.c
+++ b/6502.c
@@ -667,7 +667,7 @@ void m6502obj(int ofd)
 
 	// Write out mandatory $FFFF header
 	header[0] = header[1] = 0xFF;
-	ssize_t unused = write(ofd, header, 2);
+	uint32_t unused = write(ofd, header, 2);
 
 	for(uint16_t * l=&orgmap[0][0]; l<currentorg; l+=2)
 	{
diff --git a/eagen0.c b/eagen0.c
index 11e648a..533dfa2 100644
--- a/eagen0.c
+++ b/eagen0.c
@@ -9,12 +9,12 @@
 
 int eaNgen(WORD siz)
 {
-	uint32_t vbd, v = (uint32_t)aNexval;
-	WORD wbd, w = (WORD)(aNexattr & DEFINED);
-	WORD tdbbd, tdb = (WORD)(aNexattr & TDB);
-	vbd = (uint32_t)aNbdexval;
-	wbd = (WORD)(aNbdexattr & DEFINED);
-	tdbbd = (WORD)(aNbdexattr & TDB);
+	uint32_t v = (uint32_t)aNexval;
+	WORD w = (WORD)(aNexattr & DEFINED);
+	WORD tdb = (WORD)(aNexattr & TDB);
+	uint32_t vbd = (uint32_t)aNbdexval;
+	WORD wbd = (WORD)(aNbdexattr & DEFINED);
+	WORD tdbbd = (WORD)(aNbdexattr & TDB);
 	uint8_t extDbl[12];
 
 	switch (amN)
@@ -31,6 +31,7 @@ int eaNgen(WORD siz)
 	case AM_NONE:
 		// This is a performance hit, though
 		break;
+
 	case ADISP:
 		// expr(An)
 		if (w)
@@ -82,6 +83,7 @@ int eaNgen(WORD siz)
 		}
 
 		break;
+
 	case PCDISP:
 		if (w)
 		{
@@ -104,6 +106,7 @@ int eaNgen(WORD siz)
 		}
 
 		break;
+
 	case AINDEXED:
 		// Compute ixreg and size+scale
 		w = (WORD)((aNixreg << 12) | aNixsiz);
@@ -129,6 +132,7 @@ int eaNgen(WORD siz)
 		}
 
 		break;
+
 	case PCINDEXED:
 		// Compute ixreg and size+scale
 		w = (WORD)((aNixreg << 12) | aNixsiz);
@@ -155,6 +159,7 @@ int eaNgen(WORD siz)
 		}
 
 		break;
+
 	case IMMED:
 		switch (siz)
 		{
@@ -176,6 +181,7 @@ int eaNgen(WORD siz)
 			}
 
 			break;
+
 		case SIZW:
 		case SIZN:
 			if (w)
@@ -195,6 +201,7 @@ int eaNgen(WORD siz)
 			}
 
 			break;
+
 		case SIZL:
 			if (w)
 			{
@@ -210,6 +217,7 @@ int eaNgen(WORD siz)
 			}
 
 			break;
+
 		case SIZS:
 			// 68881/68882/68040 only
 			if (w)
@@ -235,6 +243,7 @@ int eaNgen(WORD siz)
 			}
 
     		break;
+
 		case SIZD:
 			// 68881/68882/68040 only
 			if (w)
@@ -256,6 +265,7 @@ int eaNgen(WORD siz)
 			}
 
 			break;
+
 		case SIZX:
 			// 68881/68882/68040 only
 			if (w)
@@ -271,22 +281,29 @@ int eaNgen(WORD siz)
 			}
 			else
 			{
+				// Why would this be anything other than a floating point
+				// expression???  Even if there were an undefined symbol in
+				// the expression, how would that be relevant?  I can't see
+				// any use case where this would make sense.
 				AddFixup(FU_FLOATDOUB, sloc, aNexpr);
 				memset(extDbl, 0, 12);
 				D_extend(extDbl);
 			}
 
 			break;
+
 		default:
 			// IMMED size problem
 			interror(1);
 		}
 
 		break;
+
     case SIZP:
 		// 68881/68882/68040 only
 		return error("Sorry, .p constant format is not implemented yet!");
 		break;
+
 	case ABSW:
 		if (w) // Defined
 		{
@@ -305,6 +322,7 @@ int eaNgen(WORD siz)
 		}
 
 		break;
+
 	case ABSL:
 		if (w) // Defined
 		{
@@ -320,12 +338,15 @@ int eaNgen(WORD siz)
 		}
 
 		break;
+
 	case DINDW:
 		D_word((0x190 | (aNixreg << 12)));
 		break;
+
 	case DINDL:
 		D_word((0x990 | (aNixreg << 12)));
 		break;
+
 	case ABASE:
 	case MEMPOST:
 	case MEMPRE:
@@ -333,6 +354,7 @@ int eaNgen(WORD siz)
 	case PCMPOST:
 	case PCMPRE:
 		D_word(aNexten);
+
 		// Deposit bd (if not suppressed)
 		if ((aNexten & 0x0030) == EXT_BDSIZE0)
 		{
@@ -355,7 +377,7 @@ int eaNgen(WORD siz)
 			else
 			{
 				// Arrange for fixup later on
-				AddFixup(FU_WORD | FU_SEXT, sloc, aNbexpr);
+				AddFixup(FU_WORD | FU_SEXT | FU_PCRELX, sloc, aNbexpr);
 				D_word(0);
 			}
 		}
@@ -377,6 +399,7 @@ int eaNgen(WORD siz)
 				D_long(0);
 			}
 		}
+
 		// Deposit od (if not suppressed)
 		if ((aNexten & 7) == EXT_IISPRE0 || (aNexten & 7) == EXT_IISPREN
 			|| (aNexten & 7) == EXT_IISNOIN || (aNexten & 7) == EXT_IISPOSN)
@@ -426,6 +449,7 @@ int eaNgen(WORD siz)
 
 		break;
 		//return error("unsupported 68020 addressing mode");
+
 	default:
 		// Bad addressing mode in ea gen
 		interror(3);
diff --git a/object.c b/object.c
index 29fd8f3..24c285c 100644
--- a/object.c
+++ b/object.c
@@ -321,7 +321,7 @@ int WriteObject(int fd)
 	uint8_t * buf;			// Scratch area
 	uint8_t * p;			// Temporary ptr
 	LONG trsize, drsize;	// Size of relocations
-	long unused;			// For supressing 'write' warnings
+	uint32_t unused;		// For supressing 'write' warnings
 
 	if (verb_flag)
 	{
@@ -810,7 +810,7 @@ for(int j=0; j<i; j++)
 			WriteP56();
 
 		// Write all the things |o/
-		ssize_t unused = write(fd, buf, chptr - buf);
+		unused = write(fd, buf, chptr - buf);
 
 		if (buf)
 			free(buf);
diff --git a/sect.c b/sect.c
index 7fcb299..c758063 100644
--- a/sect.c
+++ b/sect.c
@@ -455,12 +455,18 @@ int ResolveFixups(int sno)
 		//
 		// PC-relative fixups must be DEFINED and either in the same section
 		// (whereupon the subtraction takes place) or ABS (with no subtract).
-		if (dw & FU_PCREL)
+		if ((dw & FU_PCREL) || (dw & FU_PCRELX))
 		{
 			if (eattr & DEFINED)
 			{
 				if (tdb == sno)
+				{
 					eval -= loc;
+
+					// In this instruction the PC is located a DWORD away
+					if (dw & FU_PCRELX)
+						eval += 2;
+				}
 				else if (tdb)
 				{
 					// Allow cross-section PCREL fixups in Alcyon mode
@@ -483,6 +489,10 @@ int ResolveFixups(int sno)
 						}
 
 						eval -= loc;
+
+						// In this instruction the PC is located a DWORD away
+						if (dw & FU_PCRELX)
+							eval += 2;
 					}
 					else
 					{
@@ -495,8 +505,15 @@ int ResolveFixups(int sno)
 					warn("unoptimized short branch");
 			}
 			else if (obj_format == MWC)
+			{
 				eval -= loc;
 
+				// In this instruction the PC is located a DWORD away
+				if (dw & FU_PCRELX)
+					eval += 2;
+			}
+
+			// Be sure to clear any TDB flags, since we handled it just now
 			tdb = 0;
 			eattr &= ~TDB;
 		}
diff --git a/sect.h b/sect.h
index fb1db43..4de4bbf 100644
--- a/sect.h
+++ b/sect.h
@@ -84,6 +84,7 @@
 
 #define FU_SEXT      0x0010		// Ok to sign extend
 #define FU_PCREL     0x0020		// Subtract PC first
+#define FU_PCRELX    0x1000000	// 030 variant
 #define FU_EXPR      0x0040		// Expression (not symbol) follows
 
 #define FU_GLOBAL    0x0080		// Mark global symbol
-- 
2.37.2