Use real symbols instead of binary + N

src/binary.s

@@ -1,5 +1,3 @@
-.EXPORT binary
-
 ##########
 # start of the binary to execute
 #
@@ -15,27 +13,32 @@
 # also used by heap.s in libxib. The VM without a binary must not use the heap unless it takes
 # care the overlap between the heap and the appended binary image.
 
-binary:
+# Header of the binary to execute. In this case there is no built-in binary,
+# so we just define the symbols to make the VM compile
 
-# After this we expect:
-#
-# binary_start_address:
-#    db  0x12345      # start at address 0x12345; or
-#    db  -1           # start at the reset vector (default 6502 behavior)
-#
-# binary_load_address:
-#    db  0xc000       # load address of the binary image in 6502 memory
-#
-# tracing:
-#    db  1            # 0 - disable tracing, -1 - trace always, >0 - start tracing after passing that address
-#
-# vm_callback:
-#    db  0xabcde      # optional callback function to call before each instruction
-#
-# binary_length:
-#    db  0x4000       # size of the binary image
-#
-# binary_data:
-#    ds  0x4000, 0    # binary image data
+.EXPORT binary_start_address
+.EXPORT binary_load_address
+.EXPORT binary_enable_tracing
+.EXPORT binary_vm_callback
+.EXPORT binary_length
+.EXPORT binary_data
+
+# Initial pc value, or -1 to use the reset vector
++0 = binary_start_address:
+
+# Load address of the binary image in 6502 memory
++1 = binary_load_address:
+
+# Tracing (0 - disable tracing, -1 - trace always, >0 - tracing past given address)
++2 = binary_enable_tracing:
+
+# Optional callback function to call before each instruction, zero if not used
++3 = binary_vm_callback:
+
+# Size of the binary image
++4 = binary_length:
+
+# Binary image data
++5 = binary_data:
 
 .EOF

src/exec.s

@@ -2,8 +2,9 @@
 .EXPORT execute_nop
 .EXPORT invalid_opcode
 
-# From binary.s
-.IMPORT binary
+# From the linked 6502 binary
+.IMPORT binary_enable_tracing
+.IMPORT binary_vm_callback
 
 # From error.s
 .IMPORT report_error
@@ -30,28 +31,28 @@ execute:
 
 execute_loop:
     # Skip tracing if disabled
-    jz  [binary + 2], execute_tracing_done
+    jz  [binary_enable_tracing], execute_tracing_done
 
-    # If the [binary + 2] flag is positive, we use it as an address
+    # If the [binary_enable_tracing] flag is positive, we use it as an address
     # starting from where we should turn on tracing
-    eq  [binary + 2], [reg_pc], [rb + tmp]
+    eq  [binary_enable_tracing], [reg_pc], [rb + tmp]
     jz  [rb + tmp], execute_tracing_different_address
 
     # Address match, turn on tracing
-    add -1, 0, [binary + 2]
+    add -1, 0, [binary_enable_tracing]
 
 execute_tracing_different_address:
     # Print trace if enabled
-    eq  [binary + 2], -1, [rb + tmp]
+    eq  [binary_enable_tracing], -1, [rb + tmp]
     jz  [rb + tmp], execute_tracing_done
 
     call print_trace
 
 execute_tracing_done:
     # Call the callback if enabled
-    jz  [binary + 3], execute_callback_done
+    jz  [binary_vm_callback], execute_callback_done
 
-    call [binary + 3]
+    call [binary_vm_callback]
     jnz [rb - 2], execute_callback_done
 
     # Callback returned 0, halt

src/func_test_header.s

@@ -3,25 +3,29 @@
 
 # The binary is available in git repository https://github.com/Klaus2m5/6502_65C02_functional_tests
 
-.EXPORT binary
+.EXPORT binary_start_address
+.EXPORT binary_load_address
+.EXPORT binary_enable_tracing
+.EXPORT binary_vm_callback
 
 .IMPORT func_test_callback
 
-binary:
-    # Start address for the functional test binary
-    # Can be found using bin_files/6502_functional_test.lst, search for "Program start address is at"
+# Initial pc value; can be found using bin_files/6502_functional_test.lst, search for "Program start address is at"
+binary_start_address:
     db  0x0400
 
-    # Load address for the functional test binary
+# Load address for the functional test binary
+binary_load_address:
     db  0
 
-    # Set up tracing
-    #  0 - disable tracing
-    # -1 - trace always
-    # >0 - start tracing after passing that address
+# Tracing (0 - disable tracing, -1 - trace always, >0 - tracing past given address)
+binary_enable_tracing:
     db  0
 
-    # Callback address
+# Optional callback function to call before each instruction, zero if not used
+binary_vm_callback:
     db  func_test_callback
 
+# Symbols binary_length and binary data are provided by func_test_data.o
+
 .EOF

src/memory.s

@@ -4,8 +4,10 @@
 .EXPORT push
 .EXPORT pull
 
-# From binary.s
-.IMPORT binary
+# From the linked 6502 binary
+.IMPORT binary_load_address
+.IMPORT binary_length
+.IMPORT binary_data
 
 # From error.s
 .IMPORT report_error
@@ -28,13 +30,13 @@ init_memory:
     # Initialize memory space for the 6502.
 
     # Validate the load address is a valid 16-bit number
-    add [binary + 1], 0, [rb - 1]
+    add [binary_load_address], 0, [rb - 1]
     add 0xffff, 0, [rb - 2]
     arb -2
     call check_range
 
     # Validate the image will fit to 16-bits when loaded there
-    add [binary + 1], [binary + 4], [rb + tgt]
+    add [binary_load_address], [binary_length], [rb + tgt]
     lt  0x10000, [rb + tgt], [rb + tmp]
     jz  [rb + tmp], init_memory_load_address_ok
 
@@ -44,19 +46,19 @@ init_memory:
 
 init_memory_load_address_ok:
     # The 6502 memory space will start where the binary starts now
-    add binary + 5, 0, [mem]
+    add binary_data, 0, [mem]
 
     # Do we need to move the binary to a different load address?
-    jz  [binary + 1], init_memory_done
+    jz  [binary_load_address], init_memory_done
 
     # Yes, calculate beginning address of the source (binary),
-    add binary + 5, 0, [rb + src]
+    add binary_data, 0, [rb + src]
 
     # Calculate the beginning address of the target ([mem] + [load])
-    add [mem], [binary + 1], [rb + tgt]
+    add [mem], [binary_load_address], [rb + tgt]
 
     # Number of bytes to copy
-    add [binary + 4], 0, [rb + cnt]
+    add [binary_length], 0, [rb + cnt]
 
 init_memory_loop:
     # Move the image from src to tgt (iterating in reverse direction)

src/msbasic_header.s

@@ -1,19 +1,27 @@
 # This the header for the MS Basic binary.
 # It needs to be linked immediately after binary.o and immediately before the MS Basic binary itself.
 
-.EXPORT binary
+.EXPORT binary_start_address
+.EXPORT binary_load_address
+.EXPORT binary_enable_tracing
+.EXPORT binary_vm_callback
 
-binary:
-    # Start address for the MS Basic binary, set to -1 to use the reset vector.
+# Initial pc value; use the reset vector
+binary_start_address:
     db  -1
 
-    # Load address for the MS Basic binary, needs to match the BASROM memory region in $(MSBASICDIR)/vm6502.cfg.
+# Load address for the MS Basic binary; needs to match the BASROM memory region in $(MSBASICDIR)/vm6502.cfg.
+binary_load_address:
     db  0xc000
 
-    # Disable tracing
+# Tracing (0 - disable tracing, -1 - trace always, >0 - tracing past given address)
+binary_enable_tracing:
     db  0
 
-    # No callback
+# Optional callback function to call before each instruction, zero if not used
+binary_vm_callback:
     db  0
 
+# Symbols binary_length and binary data are provided by msbasic_data.o
+
 .EOF

src/state.s

@@ -16,8 +16,8 @@
 .EXPORT pack_sr
 .EXPORT unpack_sr
 
-# From binary.s
-.IMPORT binary
+# From the linked 6502 binary
+.IMPORT binary_start_address
 
 # From error.s
 .IMPORT report_error
@@ -62,7 +62,7 @@ init_state:
     arb -1
 
     # Load the start address to pc
-    add [binary + 0], 0, [reg_pc]
+    add [binary_start_address], 0, [reg_pc]
 
     # If it is -1, use the reset vector
     eq  [reg_pc], -1, [rb + tmp]