Compression of non-AIF images was broken.

xpand would correctly decompress old non-AIF images, and the broken non-AIF
images generated by recent versions of squeeze, but needed to be changed to
also decompress the new non-AIF images.
Memory limit check now always occurs if running in the application slot,
regardless of whether we were loaded at &8000 - the check was not performed
reliably for non-AIF images either.

Version 5.08. Tagged as 'squeeze-5_08'

VersionNum

-/* (5.07)
+/* (5.08)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
- * Last processed by srccommit version: 1.64.
+ * Last processed by srccommit version: 1.68.
  *
  */
-#define Module_MajorVersion_CMHG        5.07
+#define Module_MajorVersion_CMHG        5.08
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                02 Jul 2002
+#define Module_Date_CMHG                15 Oct 2002
 
-#define Module_MajorVersion             "5.07"
-#define Module_Version                  507
+#define Module_MajorVersion             "5.08"
+#define Module_Version                  508
 #define Module_MinorVersion             ""
-#define Module_Date                     "02 Jul 2002"
+#define Module_Date                     "15 Oct 2002"
 
-#define Module_ApplicationDate2         "02-Jul-02"
-#define Module_ApplicationDate4         "02-Jul-2002"
+#define Module_ApplicationDate          "15-Oct-02"
 
 #define Module_ComponentName            "squeeze"
 #define Module_ComponentPath            "RiscOS/Tools/Sources/squeeze"
 
-#define Module_FullVersion              "5.07"
-#define Module_HelpVersion              "5.07 (02 Jul 2002)"
-#define Module_LibraryVersionInfo       "5:7"
+#define Module_FullVersion              "5.08"
+#define Module_HelpVersion              "5.08 (15 Oct 2002)"
+#define Module_LibraryVersionInfo       "5:8"

c/xpand

@@ -70,6 +70,8 @@ extern int *asmcall_exit;
 static int debug;
 static int verbose;
 
+#undef AIFPRELUDE /* musn't rely on this constant - it's changed over time */
+
 /*
  * Veneer on file-handling.
  */
@@ -143,6 +145,23 @@ static int immfield(word inst) {
   return ROR(val, shift);
 }
 
+static SqueezeHeader *find_squeeze_header(int isaif, int *decompress)
+{
+    /*
+     * The size of the decoded thing is stored 6 words before the
+     * start of the unsqueezing code (see squeeze.c).
+     */
+    if (!isaif) {
+        /*
+         * Non-AIF images skip the first few instructions of the unsqueezing
+         * code; this has changed over time, so search backwards for
+         * MOV R0, #<imm>, which is always the first instruction
+         */
+        while (((*decompress & 0xfffff000) != 0xe3a00000)) decompress--;
+    }
+    return (SqueezeHeader *) (decompress-SQUEEZEWORDS);
+}
+
 static int xpand(char *in, char *out)
 {   _kernel_osfile_block info;
     bool isaif, isdata;
@@ -198,14 +217,8 @@ static int xpand(char *in, char *out)
     else
 	isdata = NO, isaif = NO;
 
-    /*
-     * The size of the decoded thing is stored 6 words before the
-     * start of the unsqueezing code (see squeeze.c).
-     */
     { int *decompress = &(((int *)hdr)[(hdr->bl_decompress & B_OFFSET) + PREFETCH]);
-      SqueezeHeader *h = (SqueezeHeader *)(isaif ? decompress-SQUEEZEWORDS :
-						   decompress-SQUEEZEWORDS-AIFPRELUDE);
-
+      SqueezeHeader *h = find_squeeze_header(isaif, decompress);
       int realsize = h->decodedsize;
       word *lastw = (word *)lastb - 1;
 

h/squeeze

@@ -33,7 +33,7 @@ typedef struct aifhdr {
 
 #define AIFBYTES   sizeof(aifhdr)  /* size in bytes of an AIF header */
 #define AIFWORDS   (AIFBYTES / sizeof(int))
-#define AIFPRELUDE 3 /* no of extra instructions in AIF decompression */
+#define AIFPRELUDE 5 /* no of extra instructions in AIF decompression */
 #define PREFETCH   2 /* words of ARM prefetch */
 
 typedef struct datahdr {

s/unsqueeze

@@ -104,6 +104,7 @@ MinLong     * 2
 |UnSqueeze_UnSqueezeBase|
 |UnsqueezeAIFImage|
         ; If it was an AIF image, we enter here and overwrite the BL decompress
+        ; xpand relies on the first instruction here being MOV r0, #<imm>
         MOV   R0, #&E1000000 ; hex for instruction MOV r0, r0
         ORR   R0, R0, #&00A00000
         SUB   R1, LR, PC     ; mode independent status bit removal
@@ -111,6 +112,9 @@ MinLong     * 2
         STR   R0, [R1, #-8]! ; overwrite the instruction we just BL'ed from
 
 |UnsqueezeADFSImage|
+        [ UnsqueezeADFSImage - UnsqueezeAIFImage <> 5*4
+        ! 1, "Change AIFPRELUDE in squeeze.h"
+        ]
         ; We arrive here knowing very little about anything.
         ; First find out where we are, and where the tables start.
 
@@ -129,25 +133,24 @@ MinLong     * 2
 
         ; SWI   &10            ; GetEnv - returns RAM limit in R1
         ; SUB   R6, R1, #&4000 ; grab 16K workspace, remember table base
-        ADR   R6, |UnSqueeze_UnSqueezeLimit|+8 ; top of squeezed image
+        ADR   R6, |UnSqueeze_UnSqueezeLimit|+24 ; top of squeezed image
         CMP   R6, R8  ; find highest of top of squeezed and unsqueezed image
-        MOVLT R6, R8  ; use SWI if you prefer... (UNIX ?)
-
-        [ expand_memcheck
-        TEQ     r1, #&8000      ; AIF at &8000 - application?
-        ]
+        MOVLO R6, R8  ; use SWI if you prefer... (UNIX ?)
 
         ; Allocate space for tables
         ADD   R1, R11, R12  ; nLongs + nShorts
         ADD   R7, R6, R1, LSL #2 ; curFree += (nLongs + nShorts) * 4;
 
 	[ expand_memcheck
-        BNE     %FT05
-	SWI	OS_GetEnv
-	ADD	R2,R7, #(8 + runImage - decodeImage)
-	CMP	R1,R2
-	BLO	expand_would_overwrite
-05
+	SWI   OS_GetEnv     ; returns RAM limit in R1
+        ; R7 points to end of tables; add space required for copied-up
+        ; decode routine.
+        ADD   R2,R7, #|UnSqueeze_UnSqueezeLimit| + 24 - decodeImage
+        ; if PC < the RAM limit, and R2 > the RAM limit, we're in trouble
+        ; (if PC > the RAM limit, we assume we're not in the application slot)
+        CMP   PC,R1
+        CMPLO R1,R2
+	BLO   expand_would_overwrite
 	]
 
         MOV   R5, R10       ; R5 is ptr into encoded tables
@@ -264,21 +267,21 @@ moveCode
 	; If we were to let the expansion occur, either a data abort would
 	; occur, or we would overwrite our parent application.
 expand_would_overwrite
-	ADR R0, error_block - 6 * 4
+	ADR   R0, error_block - 6 * 4
 	LDMIB R0!, {R1,R2,R4-R7}
-	SWI XMessageTrans_ErrorLookup
-	LDR R1,[R0]
-	TEQ R1, #0
+	SWI   XMessageTrans_ErrorLookup
+	LDR   R1,[R0]
+	TEQ   R1, #0
  	ADRNE R0, error_block_failed
-	SWI OS_GenerateError
-	DCD	0, 0, 0, 0, 0
+	SWI   OS_GenerateError
+	DCD   0, 0, 0, 0, 0
 error_block
-	DCD	0
-	DCB	"NoMem", 0
+	DCD   0
+	DCB   "NoMem", 0
 	ALIGN
 error_block_failed
-	DCD	0
-	DCB	"Not enough memory", 0
+	DCD   0
+	DCB   "Not enough memory", 0
 	ALIGN
 	]
 
@@ -325,7 +328,7 @@ long0
         LDR   R0, [R11, R0, LSL #2]    ; w = longs[(nibble-2)<<8 | *p--]
         LDRB  R1, [R10, #-1]!
         ORR   R4, R1, R0, LSL #8
-        B gotFirst
+        B     gotFirst
 notlong0
         MOVS  R4, R3            ; TMD 13-Feb-90: combine 2 instructions here
                                 ; used to be CMPS R3,#0; MOVEQ R4,R3
@@ -379,7 +382,7 @@ literal1                               ; the longer path ?
         LDRB  R1, [R10, #-1]!          ; given in ARM CPU Manual.
         ORR   R5, R0, R1, LSL #24
         STMDB R8!, {R4,R5}
-        B decodePair
+        B     decodePair
 
 doneDecode
         CMPS  R13, #0      ; Any data need to be copied elsewhere ?