Attachment 216 Details for Bug 223 – The patches!

[patch] The patches!

0001-Partial-fix-for-223-calculating-expressions-with-lab.patch (text/plain), 3.88 KB, created by ggn on 2023-12-04 10:07:16 CST

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Creator: ggn

Created: 2023-12-04 10:07:16 CST

Size: 3.88 KB

patch

obsolete

>From e359b736ef1cb46deb56739a9a59e361b919f043 Mon Sep 17 00:00:00 2001
>From: ggn <ggn@atari.org>
>Date: Mon, 4 Dec 2023 18:00:34 +0200
>Subject: [PATCH] Partial fix for #223 - calculating expressions with labels in
> different sections
>
>---
> expr.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> sect.c | 10 +++++++++-
> sect.h |  1 +
> 3 files changed, 54 insertions(+), 1 deletion(-)
>
>diff --git a/expr.c b/expr.c
>index e597257..185e54d 100644
>--- a/expr.c
>+++ b/expr.c
>@@ -582,6 +582,7 @@ be converted from a linked list into an array).
> 	return evexpr(otk, a_value, a_attr, a_esym);
> }
> 
>+extern int fixups_active;
> //
> // Evaluate expression.
> // If the expression involves only ONE external symbol, the expression is
>@@ -711,6 +712,49 @@ int evexpr(TOKEN * _tk, uint64_t * a_value, WORD * a_attr, SYM ** a_esym)
> 			}
> 			else
> 			{
>+				if (fixups_active)
>+				{
>+					// This code addresses a very specific issue found when
>+					// assembling code in ALCYON mode and outputting ST PRG
>+					// binaries. At the time of assembling the start of
>+					// TEXT, DATA and BSS is 0 based. This is because we 
>+					// have no idea how big TEXT's size is going to be in order
>+					// to know what's the offset of DATA (same for BSS).
>+					// In general, most cases are handled during fixups as
>+					// at that point everything is known, so we can adjust the
>+					// address of labels etc etc. But in the case of calculating
>+					// an expression where some of its parts are in one section
>+					// and some in another, then this won't work. Since we
>+					// most likely are going to encounter expressions that
>+					// subtract cross-section labels (at least I cannot think
>+					// of any other use case), we add checks for these cases
>+					// here but only when fixups are happening. This will
>+					// simply add the start of a DATA or BSS label to it
>+					// before doing the subtraction, so then the distance
>+					// between the two labels will be calculated correctly.
>+					// Note that this doesn't work if the labels are fixed
>+					// up before this stage.
>+					if ((sattr[0] & TDB) && (sattr[1] & TDB) && (sattr[0] & TDB) != (sattr[1] & TDB))
>+					{
>+						if (sattr[0] & DATA)
>+						{
>+							sval[0] += sect[TEXT].sloc;
>+						}
>+						else if (sattr[0] & BSS)
>+						{
>+							sval[0] += sect[TEXT].sloc + sect[DATA].sloc;
>+						}
>+						if (sattr[1] & DATA)
>+						{
>+							sval[1] += sect[TEXT].sloc;
>+						}
>+						else if (sattr[1] & BSS)
>+						{
>+							sval[1] += sect[TEXT].sloc + sect[DATA].sloc;
>+						}
>+					}
>+				}
>+
> 				*sval -= sval[1];
> 			}
> 
>diff --git a/sect.c b/sect.c
>index 12f9c89..5d7124c 100644
>--- a/sect.c
>+++ b/sect.c
>@@ -29,6 +29,9 @@ void SwitchSection(int);
> SECT sect[NSECTS];		// All sections...
> int cursect;			// Current section number
> 
>+// Globals
>+int fixups_active = 0;	// Give a heads up to expr() because it might need to take some special measures
>+
> // These are copied from the section descriptor, the current code chunk
> // descriptor and the current fixup chunk descriptor when a switch is made into
> // a section. They are copied back to the descriptors when the section is left.
>@@ -540,7 +543,7 @@ int ResolveFixups(int sno)
> 						{
> 						case TEXT:
> // Shouldn't there be a break here, since otherwise, it will point to the DATA section?
>-//							break;
>+							break;
> 						case DATA:
> 							eval += sect[TEXT].sloc;
> 							break;
>@@ -1044,6 +1047,11 @@ int ResolveAllFixups(void)
> 	if (glob_flag)
> 		ForceUndefinedSymbolsGlobal();
> 
>+	if (prg_flag)
>+	{
>+		fixups_active = 1;
>+	}
>+
> 	DEBUG printf("Resolving TEXT sections...\n");
> 	ResolveFixups(TEXT);
> 	DEBUG printf("Resolving DATA sections...\n");
>diff --git a/sect.h b/sect.h
>index 833217b..0ebca4a 100644
>--- a/sect.h
>+++ b/sect.h
>@@ -200,6 +200,7 @@ extern int cursect;
> extern SECT sect[];
> extern uint32_t challoc;
> extern CHUNK * scode;
>+extern int fixups_active;
> 
> // Prototypes
> void InitSection(void);
>-- 
>2.40.1.windows.1
>

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