Fix ACME code gen "overflow"

ACME has a "real" PC and a "pseudo" PC.  The "real" PC determines the
initial position in a 64KB buffer used to hold assembler output.  If
the amount of code generated runs off the end, the assembler fails
with "produced too much code".

The source code generator in SourceGen was outputting a "real" PC
for the first address range and "psuedo" PCs for any address ranges
that followed.  This produced nice results for code with a single
range, but caused problems for multi-range sources if the initial
range was high in memory and a later range was lower in memory.
While the assembler isn't actually generating more than 64KB of code,
ACME's buffer management was detecting an overflow.

Now, if a source file has multiple address ranges, we set the "real"
PC to $0000 and use a "pseudo" PC for all ranges.  Output for projects
with a single address range is unmodified.

SourceGen/AsmGen/AsmAcme.cs

@@ -523,19 +523,28 @@ namespace SourceGen.AsmGen {
 
         // IGenerator
         public void OutputOrgDirective(int offset, int address) {
-            // For the first one, set the "real" PC.  For all subsequent directives, set the
-            // "pseudo" PC.
+            // If there's only one address range, just set the "real" PC.  If there's more
+            // than one we can run out of space if the source file has a chunk in high memory
+            // followed by a chunk in low memory, because the "real" PC determines when the
+            // 64KB bank is overrun.
             if (offset == 0) {
-                OutputLine("*", "=", SourceFormatter.FormatHexValue(address, 4), string.Empty);
-            } else {
-                if (mInPseudoPcBlock) {
-                    // close previous block
-                    OutputLine(string.Empty, CLOSE_PSEUDOPC, string.Empty, string.Empty);
+                // first one
+                if (Project.AddrMap.Count == 1) {
+                    OutputLine("*", "=", SourceFormatter.FormatHexValue(address, 4), string.Empty);
+                    return;
+                } else {
+                    // set the real PC to address zero to ensure we get a full 64KB
+                    OutputLine("*", "=", SourceFormatter.FormatHexValue(0, 4), string.Empty);
                 }
-                OutputLine(string.Empty, sDataOpNames.OrgDirective,
-                    SourceFormatter.FormatHexValue(address, 4) + " {", string.Empty);
-                mInPseudoPcBlock = true;
             }
+
+            if (mInPseudoPcBlock) {
+                // close previous block
+                OutputLine(string.Empty, CLOSE_PSEUDOPC, string.Empty, string.Empty);
+            }
+            OutputLine(string.Empty, sDataOpNames.OrgDirective,
+                SourceFormatter.FormatHexValue(address, 4) + " {", string.Empty);
+            mInPseudoPcBlock = true;
         }
 
         // IGenerator

SourceGen/SGTestData/Expected/2004-numeric-types_acme.S

@@ -1,7 +1,8 @@
 ;Project file was edited to get all big-endian data types, and to have an
 ;incorrect .junk alignment directive.
         !cpu    6502
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         bit     L1448
         jsr     L14A8
         nop
@@ -60,6 +61,7 @@ LABEL   !hex    00112233445566778899aabbccddeeff00112233445566778899aabbccddeeff
         !fill   2,$dd      ;incorrect alignment
         !align  255,0,$00
         !fill   8,$82
+        } ;!pseudopc
         !pseudopc $1408 {
         !fill   8,$82      ;note no-op .ORG
         !fill   8,$83

SourceGen/SGTestData/Expected/2007-labels-and-symbols_acme.S

@@ -1,5 +1,6 @@
 ;ACME can't handle 65816 code that lives outside bank zero
-*       =       $012345
+*       =       $0000
+        !pseudopc $012345 {
         !hex    18fbe230a9cda9dda90da9eda9fea92da9ffa929a910a9e9a90fa945a923a901
         !hex    f4edfef44523f40100f45634f41200f4edfef44523f40100f45634f41200a5ce
         !hex    adce00afce0000adecfeafecfe00adeefeafeefe00ad4623af462301ad4423af
@@ -22,3 +23,4 @@
         !hex    656172206f6e20746865206669727374206c696e652e20205468652071756963
         !hex    6b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920
         !hex    646f67732ea97aa959a934c230a97b56a95a34a9341260
+        } ;!pseudopc

SourceGen/SGTestData/Expected/2008-address-changes_acme.S

@@ -1,5 +1,6 @@
         !cpu    65816
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         !as
         !rs
         clc
@@ -9,6 +10,7 @@
         jsr     L1107
         jmp     L2000
 
+        } ;!pseudopc
         !pseudopc $1100 {
 L1100   bit     L1100
 L1103   lda     #$11

SourceGen/SGTestData/Expected/2009-branches-and-banks_acme.S

@@ -1,6 +1,8 @@
 ;ACME can't handle 65816 code that lives outside bank zero
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         !hex    18fbe2304c00002c0000a500a503d0ba30b862b5ff7006826d00000102a51482
         !hex    a5ff2c80005c0000442cc0ff823d00cf000044af000044ad0000a50030f562b2
         !hex    ffd0b082a9ff1700170044cfc0ff44f005303c8239005c0020002c0020f41700
         !hex    f44400d003dc1300ea201220201520200f202256341260
+        } ;!pseudopc

SourceGen/SGTestData/Expected/2010-target-adjustment_acme.S

@@ -1,5 +1,6 @@
         !cpu    65816
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         !as
         !rs
 load11  lda     #$11
@@ -48,6 +49,7 @@ load11  lda     #$11
 
         !byte   $80
 @dat81  !byte   $81
+        } ;!pseudopc
         !pseudopc $2000 {
 @L2000  !byte   $82
         !byte   $83

SourceGen/SGTestData/Expected/2014-label-dp_acme.S

@@ -1,6 +1,7 @@
 ;6502bench SourceGen v1.1.0-dev1
         !cpu    65816
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         !as
         !rs
         sec
@@ -286,6 +287,7 @@ L11FC   cmp+2   L0086,x
         sbc+2   L0086,x
         inc+2   L0086,x
         sbc+3   L0089,x
+        } ;!pseudopc
         !pseudopc $0080 {
 L0080   bit+1   @L0082
 @L0082  bit+1   @L0082

SourceGen/SGTestData/Expected/2019-local-variables_acme.S

@@ -5,7 +5,8 @@ CONST_ZERO =    $f0        ;project const
 PROJ_ZERO =     $00        ;project addr
 PROJ_ONE =      $01        ;project addr
 
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         !as
         !rs
         ldy     PROJ_ZERO
@@ -187,6 +188,7 @@ L103C   lda     #$fe
         jsr     DPCODE
         rts
 
+        } ;!pseudopc
         !pseudopc $0080 {
 DPCODE  nop
         lda+1   DPCODE

SourceGen/SGTestData/Expected/2022-extension-scripts_acme.S

@@ -3,7 +3,8 @@ PrintInlineL1String = $011000
 PrintInlineL2String = $012000
 PrintInlineDciString = $013000
 
-*       =       $1000
+*       =       $0000
+        !pseudopc $1000 {
         !as
         !rs
         clc
@@ -92,6 +93,7 @@ Next1   jsr     L10BA
 
         !fill   300,$00
 
+        } ;!pseudopc
         !pseudopc $1800 {
 L1800   jsr     PrintInlineNullString
         per     $8778

SourceGen/SGTestData/Expected/2024-ui-edge-cases_acme.S

@@ -1,8 +1,10 @@
         !cpu    6502
-*       =       $2000
+*       =       $0000
+        !pseudopc $2000 {
         jmp     L2100
 
         !text   "hello, "  ;string should be split by no-op addr change
+        } ;!pseudopc
         !pseudopc $200a {
         !text   "world"
         !byte   $80