From 0505b4cfef80e2bc3fad8644c668a56c5a973b63 Mon Sep 17 00:00:00 2001
From: John Lorentzson <john_lorentzson@yahoo.com>
Date: Mon, 28 Jul 2025 12:38:56 +0200
Subject: [PATCH] Add working emulator preview build method

---
 editor/editor.lisp                |  2 +-
 host/Makefile                     | 16 +++++++++++-----
 host/src/mainloop.s               | 30 +++++++++++++++++++++---------
 user-side-compiler/interface.lisp | 22 +++++++++++++++++++---
 4 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/editor/editor.lisp b/editor/editor.lisp
index 3d8a5b1..87a3430 100644
--- a/editor/editor.lisp
+++ b/editor/editor.lisp
@@ -753,7 +753,7 @@ Additionally ensures correct line numbers on the way, as a bonus."
   (clear-screen)
   (redisplay-view (current-view *editor*)))
 
-(defparameter *refresh-asm-functions-p* nil
+(defparameter *refresh-asm-functions-p* #+swank t #-swank nil
   "If non-NIL, reload asm function addresses from listing before every compile.")
 
 (defun com-compile-buffer ()
diff --git a/host/Makefile b/host/Makefile
index 2a4e790..d36b5ec 100644
--- a/host/Makefile
+++ b/host/Makefile
@@ -1,8 +1,12 @@
-BINARY := host.prg
+HOST_BINARY := host.prg
+PREVIEW_BINARY := preview.prg
 
 BUILD_DIR := ./build
 SRC_DIR := ./src
 
+HOST_PRG := $(BUILD_DIR)/$(HOST_BINARY)
+PREVIEW_PRG := $(BUILD_DIR)/$(PREVIEW_BINARY)
+
 SRCS := $(shell find $(SRC_DIR) -name '*.s' -or -name '*.inc')
 TOPLEVEL := source.s
 
@@ -10,11 +14,13 @@ CL := cl65
 
 CLFLAGS := -u __EXEHDR__ -t c64 -C c64-asm.cfg -l $(BUILD_DIR)/host.lst -Ln $(BUILD_DIR)/host.lbl
 
-$(BUILD_DIR)/$(BINARY): $(SRCS)
+$(HOST_PRG): $(SRCS)
 	mkdir -p $(BUILD_DIR)
 	$(CL) -o $@ $(CLFLAGS) $(SRC_DIR)/$(TOPLEVEL)
 
-all: $(BUILD_DIR)/$(BINARY)
+$(PREVIEW_PRG): $(SRCS) userprog.bin
+	$(CL) -o $@ --asm-define EMULATOR_PREVIEW $(CLFLAGS) $(SRC_DIR)/$(TOPLEVEL)
 
-preview: userprog.bin $(SRCS)
-	$(CL) -o $@ -D EMULATOR_PREVIEW $(CLFLAGS) $(SRC_DIR)/$(TOPLEVEL)
+all: $(HOST_PRG)
+
+preview: $(PREVIEW_PRG)
diff --git a/host/src/mainloop.s b/host/src/mainloop.s
index 6612125..3e5cc13 100644
--- a/host/src/mainloop.s
+++ b/host/src/mainloop.s
@@ -1,15 +1,18 @@
 ;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
 .scope mainsetup
-;; 	USERPROG	=	$C000
-;; 	.repeat 4, I
-;; 	ldy #$00
-;; :
-;; 	lda batch_userprog+(I*256),Y
-;; 	sta USERPROG+(I*256),Y
-;; 	dey
-;; 	bne :-
-;; 	.endrep
+.ifdef EMULATOR_PREVIEW
+ 	USERPROG	=	$C000
+.repeat 4, I
+ 	ldy #$00
+ :
+ 	lda batch_userprog+(I*256),Y
+ 	sta USERPROG+(I*256),Y
+ 	dey
+ 	bne :-
+.endrep
+.endif
 
+.ifndef EMULATOR_PREVIEW
 @waitstart: ;; Wait until joystick 2 has been pulled down to start the program
 	dec $d020
 	lda $dc00
@@ -29,12 +32,19 @@
 
 	jsr maybe_download_userprog
 	beq @trying
+.endif
 .endscope
 
 	lda #$0d
 	sta $d020
 
 .scope mainloop
+
+	ldx #$00
+	stx FRAMECOUNT
+	inx
+	sta FIRSTTIME
+
 ml:
 	USERPROG	=	$C000
 	RASTER		=	$D012
@@ -44,6 +54,7 @@ ml:
 	ora $01
 	sta $01
 
+.ifndef EMULATOR_PREVIEW
 	jsr maybe_download_userprog
 	beq @nochange
 	ldx #$00
@@ -51,6 +62,7 @@ ml:
 	inx
 	sta FIRSTTIME
 @nochange:
+.endif
 	jsr USERPROG
 
 	;; Bank out character ROM, I/O in
diff --git a/user-side-compiler/interface.lisp b/user-side-compiler/interface.lisp
index 145ab1a..4938734 100644
--- a/user-side-compiler/interface.lisp
+++ b/user-side-compiler/interface.lisp
@@ -221,12 +221,15 @@
       (format t "Finished, wrote compiled program to \"~A\".~%"
               output-filepath))))
 
-(defun send-data-to-c64 (data)
+(defparameter *c64-tty* "/dev/ttyACM0")
+
+(defun %send-data-to-c64 (data)
   (declare (type vector data))
-  (with-open-file (stream "/dev/ttyACM0"
+  (with-open-file (stream *c64-tty*
                           :direction :io
                           :element-type '(unsigned-byte 8)
-                          :if-exists :overwrite)
+                          :if-exists :overwrite
+                          :if-does-not-exist :error)
     (sleep 2.5)
     (let ((index 0)
           (length (length data)))
@@ -245,6 +248,19 @@
                 (force-output stream)
                 (format t "~D~%" index)))))
 
+(defun send-data-to-c64 (data)
+  (declare (type vector data))
+  (handler-bind
+      ((file-error
+         (lambda (c)
+           (when (equalp (namestring (file-error-pathname c))
+                         (namestring *c64-tty*))
+             (warn "Failed to open C64 transfer TTY.")
+             (abort c)))))
+    (restart-case
+        (%send-data-to-c64 data)
+      (abort ()))))
+
 (defun compile-and-send-to-c64 (string)
   (let ((bytes (compile-string-to-bytes string :print-ir-p t)))
     (send-data-to-c64 (coerce bytes 'vector))))