From b176847778577943a95ceefeb77eafee9c69a724 Mon Sep 17 00:00:00 2001
From: Dave Schmenk <dschmenk@gmail.com>
Date: Sun, 14 Jan 2018 21:41:47 -0800
Subject: [PATCH] Reduce stack usage for ENTER/LEAVE but incompatible bytecode

---
 src/toolsrc/codegen.c   |  4 ++--
 src/toolsrc/codegen.pla |  3 ++-
 src/vmsrc/cmd.pla       |  6 +++---
 src/vmsrc/plvm02.s      |  6 ++++--
 src/vmsrc/plvm802.s     | 25 +++++++++++++------------
 5 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/src/toolsrc/codegen.c b/src/toolsrc/codegen.c
index 4060438..06b8791 100755
--- a/src/toolsrc/codegen.c
+++ b/src/toolsrc/codegen.c
@@ -354,7 +354,7 @@ void emit_header(void)
     {
         printf("\t%s\t_SEGEND-_SEGBEGIN\t; LENGTH OF HEADER + CODE/DATA + BYTECODE SEGMENT\n", DW);
         printf("_SEGBEGIN%c\n", LBL);
-        printf("\t%s\t$DA7F\t\t\t; MAGIC #\n", DW);
+        printf("\t%s\t$6502\t\t\t; MAGIC #\n", DW);
         printf("\t%s\t_SYSFLAGS\t\t\t; SYSTEM FLAGS\n", DW);
         printf("\t%s\t_SUBSEG\t\t\t; BYTECODE SUB-SEGMENT\n", DW);
         printf("\t%s\t_DEFCNT\t\t\t; BYTECODE DEF COUNT\n", DW);
@@ -802,7 +802,7 @@ void emit_leave(void)
 {
     emit_pending_seq();
     if (localsize)
-        printf("\t%s\t$5A\t\t\t; LEAVE\n", DB);
+        printf("\t%s\t$5A,$%02X\t\t\t; LEAVE\t%d\n", DB, localsize, localsize);
     else
         printf("\t%s\t$5C\t\t\t; RET\n", DB);
 }
diff --git a/src/toolsrc/codegen.pla b/src/toolsrc/codegen.pla
index 6259e98..82a2a95 100644
--- a/src/toolsrc/codegen.pla
+++ b/src/toolsrc/codegen.pla
@@ -190,6 +190,7 @@ def emit_leave#0
     emit_pending_seq
     if framesize
         emit_byte($5A)
+        emit_byte(framesize)
     else
         emit_byte($5C)
     fin
@@ -805,7 +806,7 @@ def writeheader(refnum)
     len       = moddep - 1 - @header
     modfix    = len + RELADDR - codebuff // Convert generated address into module adress
     header:0  = len + codeptr - codebuff // sizeof header+data+bytecode
-    header:2  = $DA7F                    // Magic #
+    header:2  = $6502                    // Magic #
     header:4  = modsysflags              // Module SYSFLAGS
     header:6  = len + RELADDR + datasize // Byte code offset
     header:8  = def_cnt                  // DEFinition count
diff --git a/src/vmsrc/cmd.pla b/src/vmsrc/cmd.pla
index e04a223..9f229a4 100755
--- a/src/vmsrc/cmd.pla
+++ b/src/vmsrc/cmd.pla
@@ -938,7 +938,7 @@ def loadmod(mod)#1
         moddep  = @header.1
         defofst = modsize + RELADDR
         init    = 0
-        if rdlen > 4 and header:2 == $DA7F // DAVE+1 = magic number :-)
+        if rdlen > 4 and header:2 == $6502 // DAVE+1 = magic number :-)
             //
             // This is an EXTended RELocatable (data+bytecode) module.
             //
@@ -951,7 +951,7 @@ def loadmod(mod)#1
             // Load module dependencies.
             //
             while ^moddep
-                if !lookuptbl(moddep, symtbl)//lookupmod(moddep)
+                if !lookuptbl(moddep, symtbl)
                     close(refnum)
                     refnum = 0
                     if loadmod(moddep) < 0
@@ -995,7 +995,7 @@ def loadmod(mod)#1
         //
         // Add module to symbol table.
         //
-        addsym(mod, modaddr)//addmod(mod, modaddr)
+        addsym(mod, modaddr)
         //
         // Apply all fixups and symbol import/export.
         //
diff --git a/src/vmsrc/plvm02.s b/src/vmsrc/plvm02.s
index 5476ea6..d43cc4c 100755
--- a/src/vmsrc/plvm02.s
+++ b/src/vmsrc/plvm02.s
@@ -1528,7 +1528,7 @@ JMPTMP  JMP     (TMP)
 ;*
 ENTER   INY
         LDA     (IP),Y
-        PHA                     ; SAVE ON STACK FOR LEAVE
+;        PHA                     ; SAVE ON STACK FOR LEAVE
         EOR     #$FF            ; ALLOCATE FRAME
         SEC
         ADC     PPL
@@ -1560,7 +1560,9 @@ LEAVEX  STA     ALTRDOFF
         LDA     PSR
         PHA
         PLP
-LEAVE   PLA                     ; DEALLOCATE POOL + FRAME
+LEAVE   ;PLA                     ; DEALLOCATE POOL + FRAME
+        +INC_IP
+        LDA     (IP),Y
         CLC
         ADC     IFPL
         STA     PPL
diff --git a/src/vmsrc/plvm802.s b/src/vmsrc/plvm802.s
index 38db704..d734bf4 100644
--- a/src/vmsrc/plvm802.s
+++ b/src/vmsrc/plvm802.s
@@ -1517,8 +1517,8 @@ ENTER   INY
         STA     $7D0+31
         PLA
 }
-        PHA                     ; SAVE ON STACK FOR LEAVE
-        DEC     HWSP            ; UPDATE HWSP TO SKIP FRAME SIZE
+        ;PHA                     ; SAVE ON STACK FOR LEAVE
+        ;DEC     HWSP            ; UPDATE HWSP TO SKIP FRAME SIZE
         +ACCMEM16               ; 16 BIT A/M
 ;        AND     #$00FF
         EOR     #$FFFF          ; ALLOCATE FRAME
@@ -1549,7 +1549,16 @@ ENTER   INY
 ;* LEAVE FUNCTION
 ;*
 LEAVEX  STX     ALTRDOFF
-LEAVE   +ACCMEM8                ; 8 BIT A/M
+LEAVE   ;PLA                     ; DEALLOCATE POOL + FRAME
+        +INC_IP
+        LDA     (IP),Y
+        AND     #$00FF
+        CLC
+        ADC     IFP
+        STA     PP
+        PLA                     ; RESTORE PREVIOUS FRAME
+        STA     IFP
+        +ACCMEM8                ; 8 BIT A/M
         TSC                     ; MOVE HW EVAL STACK TO ZP EVAL STACK
         EOR     #$FF
         SEC
@@ -1587,15 +1596,7 @@ LEAVE   +ACCMEM8                ; 8 BIT A/M
         LDX     $C010
 +       LDX     TMPL
 }
-        TYX                     ; RESTORE NEW ESP
-        PLA                     ; DEALLOCATE POOL + FRAME
-        +ACCMEM16               ; 16 BIT A/M
-        AND     #$00FF
-        CLC
-        ADC     IFP
-        STA     PP
-        PLA                     ; RESTORE PREVIOUS FRAME
-        STA     IFP
+        TYX                     ; RESTORE NEW ESP        
         SEC                     ; SWITCH TO EMULATED MODE
         XCE
         !AS