Treat ORG records as giving a signed offset from the current location.

This is the way they are defined in the GS/OS Reference, as well as the way they seem to be used by all assemblers and all other linkers that I could check (ORCA/M, MPW AsmIIGS, Apple LinkIIGS, old ORCA/APW LINKED, 8-bit ORCA linker).

Previously, this linker treated ORG records as giving an absolute address to ORG to (but with a bug in the address computation). The OMF spec in appendix B of the ORCA/M manual defines them this way, but this is inconsistent with the spec in the GS/OS Reference and with the way ORG records are generated by ORCA/M itself (for an ORG *+expression directive). Therefore, I think this is just an error and the specification in the GS/OS Reference should be regarded as correct.

We still do not support going backward (using a negative ORG operand). Trying to do so will just give an error.

exp.asm

@@ -727,6 +727,7 @@ addr	dc	a'EndExp'	$00		End
 *	shiftFlag - 1 if the value is shifted, else 0
 *	shiftValue - expression result before shifting
 *	shiftCount - shift counter
+*	symbolRelocatable - non-zero if sym is relocatable
 *	returns the value of the expression
 *
 ****************************************************************

linker.notes

@@ -10,6 +10,14 @@ Updated 2022
 	    2.	A load segment is now flagged as position-independent only if
 		all the constituent object segments have that attribute set.
 
+	    3.	Fixed bug that caused EQU or GEQU expressions with non-constant
+		operands to be evaluated incorrectly.
+
+	    4.	The numeric value in an ORG record is now treated as a signed
+		offset from the current location, consistent with its
+		definition in the GS/OS Reference.  However, negative offset
+		values are not supported and will produce an error.
+
 2.0.6       1.	The linker could give a spurious error about the relative
 		address calculation for a BRL instruction if it branched
 		forward or backward more than 32 KB.  Since the address
@@ -66,7 +74,9 @@ Updated 2022
 
 -- Documentation Update -----------------------------------------------------
 
-No changes.
+ORCA/M Manual, p. 492
+
+The operand in an ORG record is a signed offset from the current location, not an absolute address.  (This is consistent with the definition in the GS/OS Reference, and with the behavior of ORCA/M and other assemblers and linkers.)
 
 -- Changes introduced in ORCA/Linker 2.1.0 ----------------------------------
 

pass1.asm

@@ -137,13 +137,12 @@ DoOrg	private
 	sta	r0
 	ldy	#3
 	lda	[sp],Y
-	sta	r2+2
+	sta	r2
 	add4	sp,#5
 
-	sub4	r0,loadOrg	get the disp from the segment start
-	cmpl	pc,r0
-	bge	lb1	if the disp is greater than the pc then
-	move4 r0,pc	  update the pc
+	lda	r2
+	bmi	lb1	if the disp is positive
+	add4	pc,r0	  update the pc
 lb1	anop
 	rts
 	end

pass2.asm

@@ -643,13 +643,12 @@ DoOrg	private
 
 	ldy	#1	get the value
 	lda	[sp],Y
-	sta	r4
+	sta	r0
 	ldy	#3
 	lda	[sp],Y
-	sta	r6
+	sta	r2
 	add4	sp,#5	skip the op code & operand
-	sub4	pc,r4,r0	calculate the space to insert
-	lda	r2	if space < 0 then
+	lda	r2	if disp < 0 then
 	bpl	lb1
 	ph4	#0	  Error(NULL,3)
 	ph2	#3

symbol.asm

@@ -845,15 +845,10 @@ gb3	ldy	#symPriv	if sym^.symPriv then
 sv1	ldy	#symExp	if the value is an expression then
 	lda	[sym],Y
 	jeq	sv2
-	ph2	copiedExpression	  save volitile variables
+	ph2	copiedExpression	  save volatile variables
 	ph4	shiftCount
 	ph2	shiftFlag
 	ph4	shiftValue
-	ph2	symbolCount
-	ph2	symbolLength
-	ph2	symbolRelocatable
-	ph2	symbolType
-	ph4	symbolValue
 	ldy	#symVal+2	  evaluate the expression
 	lda	[sym],Y
 	pha
@@ -864,23 +859,14 @@ sv1	ldy	#symExp	if the value is an expression then
 	jsr	Evaluate
 	sta	symbolValue	  save the value
 	stx	symbolValue+2
-	lda	shiftFlag	  if the value is shifted then
-	beq	sv1a
-	ph4	name	    flag the error
-	ph2	#2
-	jsr	Error
 sv1a	lda	symbolRelocatable	  if the symbol is relocatable then
 	beq	sv1c
-	jsr	CheckSegment	    check for errors
-	ldy	#symSeg	    set the expression file
-	lda	[sym],Y
-	sta	expSegment
-sv1c	pl4	symbolValue	  restore volitile variables
-	pl2	symbolType
-	pl2	symbolRelocatable
-	pl2	symbolLength
-	pl2	symbolCount
-	pl4	shiftValue
+	lda	shiftFlag	    if the value is shifted then
+	beq	sv1c
+	ph4	name	      flag the error
+	ph2	#2
+	jsr	Error
+sv1c	pl4	shiftValue	  restore volatile variables
 	pl2	shiftFlag
 	pl4	shiftCount
 	pl2	copiedExpression