From a5b4849058157d166ec4b5463ccaec6b82d493d4 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Fri, 29 Dec 2017 14:17:51 +0100
Subject: [PATCH] fixes

---
 il65/codegen.py | 77 +++++++++++++++++++++++++++++++++++--------------
 lib/c64lib.ill  | 18 +++++++-----
 2 files changed, 65 insertions(+), 30 deletions(-)

diff --git a/il65/codegen.py b/il65/codegen.py
index 5442264b4..127623700 100644
--- a/il65/codegen.py
+++ b/il65/codegen.py
@@ -406,15 +406,18 @@ class CodeGenerator:
         is_incr = isinstance(stmt, ParseResult.InplaceIncrStmt)
         if isinstance(stmt.what, ParseResult.RegisterValue):
             reg = stmt.what.register
+            # note: these operations below are all checked to be ok
             if is_incr:
                 if reg == 'A':
+                    # a += 1..255
                     self.p("\t\tclc")
                     self.p("\t\tadc  #{:d}".format(stmt.howmuch))
                 elif reg in REGISTER_BYTES:
-                    # 8 bit incr
                     if stmt.howmuch == 1:
+                        # x/y += 1
                         self.p("\t\tin{:s}".format(reg.lower()))
                     else:
+                        # x/y += 2..255
                         self.p("\t\tpha")
                         self.p("\t\tt{:s}a".format(reg.lower()))
                         self.p("\t\tclc")
@@ -422,33 +425,49 @@ class CodeGenerator:
                         self.p("\t\tta{:s}".format(reg.lower()))
                         self.p("\t\tpla")
                 elif reg == "AX":
+                    # AX += 1..255
                     self.p("\t\tclc")
-                    self.p("\t\tadc  #1")
-                    self.p("\t\tbne  +")
+                    self.p("\t\tadc  #{:d}".format(stmt.howmuch))
+                    self.p("\t\tbcc  +")
                     self.p("\t\tinx")
                     self.p("+")
                 elif reg == "AY":
+                    # AY += 1..255
                     self.p("\t\tclc")
-                    self.p("\t\tadc  #1")
-                    self.p("\t\tbne  +")
+                    self.p("\t\tadc  #{:d}".format(stmt.howmuch))
+                    self.p("\t\tbcc  +")
                     self.p("\t\tiny")
                     self.p("+")
                 elif reg == "XY":
-                    self.p("\t\tinx")
-                    self.p("\t\tbne  +")
-                    self.p("\t\tiny")
-                    self.p("+")
+                    if stmt.howmuch == 1:
+                        # XY += 1
+                        self.p("\t\tinx")
+                        self.p("\t\tbne  +")
+                        self.p("\t\tiny")
+                        self.p("+")
+                    else:
+                        # XY += 2..255
+                        self.p("\t\tpha")
+                        self.p("\t\ttxa")
+                        self.p("\t\tclc")
+                        self.p("\t\tadc  #{:d}".format(stmt.howmuch))
+                        self.p("\t\ttax")
+                        self.p("\t\tbcc  +")
+                        self.p("\t\tiny")
+                        self.p("+\t\tpla")
                 else:
                     raise CodeError("invalid incr register: " + reg)
             else:
                 if reg == 'A':
+                    # a -= 1..255
                     self.p("\t\tsec")
                     self.p("\t\tsbc  #{:d}".format(stmt.howmuch))
                 elif reg in REGISTER_BYTES:
-                    # 8 bit decr
                     if stmt.howmuch == 1:
+                        # x/y -= 1
                         self.p("\t\tde{:s}".format(reg.lower()))
                     else:
+                        # x/y -= 2..255
                         self.p("\t\tpha")
                         self.p("\t\tt{:s}a".format(reg.lower()))
                         self.p("\t\tsec")
@@ -456,22 +475,36 @@ class CodeGenerator:
                         self.p("\t\tta{:s}".format(reg.lower()))
                         self.p("\t\tpla")
                 elif reg == "AX":
-                    self.p("\t\tcmp  #0")
-                    self.p("\t\tbne  +")
+                    # AX -= 1..255
+                    self.p("\t\tsec")
+                    self.p("\t\tsbc  #{:d}".format(stmt.howmuch))
+                    self.p("\t\tbcs  +")
                     self.p("\t\tdex")
-                    self.p("+\t\tsec")
-                    self.p("\t\tsbc  #1")
+                    self.p("+")
                 elif reg == "AY":
-                    self.p("\t\tcmp  #0")
-                    self.p("\t\tbne  +")
+                    # AY -= 1..255
+                    self.p("\t\tsec")
+                    self.p("\t\tsbc  #{:d}".format(stmt.howmuch))
+                    self.p("\t\tbcs  +")
                     self.p("\t\tdey")
-                    self.p("+\t\tsec")
-                    self.p("\t\tsbc  #1")
+                    self.p("+")
                 elif reg == "XY":
-                    self.p("\t\tcpx  #0")
-                    self.p("\t\tbne  +")
-                    self.p("\t\tdey")
-                    self.p("+\t\tdex")
+                    if stmt.howmuch == 1:
+                        # XY -= 1
+                        self.p("\t\tcpx  #0")
+                        self.p("\t\tbne  +")
+                        self.p("\t\tdey")
+                        self.p("+\t\tdex")
+                    else:
+                        # XY -= 2..255
+                        self.p("\t\tpha")
+                        self.p("\t\ttxa")
+                        self.p("\t\tsec")
+                        self.p("\t\tsbc  #{:d}".format(stmt.howmuch))
+                        self.p("\t\ttax")
+                        self.p("\t\tbcs  +")
+                        self.p("\t\tdey")
+                        self.p("+\t\tpla")
                 else:
                     raise CodeError("invalid decr register: " + reg)
         elif isinstance(stmt.what, (ParseResult.MemMappedValue, ParseResult.IndirectValue)):
diff --git a/lib/c64lib.ill b/lib/c64lib.ill
index e26d9e554..63724ce63 100644
--- a/lib/c64lib.ill
+++ b/lib/c64lib.ill
@@ -540,15 +540,17 @@ sub  print_byte_decimal  (ubyte: A) -> (A?, X?, Y?)  {
 	asm {
 		jsr  byte2decimal
 		pha
-		tya
-		cmp  #'0'
-		beq  +
+		cpy  #'0'
+		bne  _print_hundreds
+		cpx  #'0'
+		bne  _print_tens
+		pla
+		jmp  c64.CHROUT
+_print_hundreds	tya
 		jsr  c64.CHROUT
-+		txa
-		cmp  #'0'
-		beq  +
+_print_tens	txa
 		jsr  c64.CHROUT
-+		pla
+		pla
 		jmp  c64.CHROUT
 	}
 }
@@ -561,7 +563,7 @@ sub  print_byte_hex  (prefix: SC, ubyte: A) -> (A?, X?, Y?)  {
 		lda  #'$'
 		jsr  c64.CHROUT
 		pla
-	+	jsr  byte2hex
++		jsr  byte2hex
 		txa
 		jsr  c64.CHROUT
 		tya