Add a custom entry point to the user code

The routine does not have to start from the first byte of machine code

Makefile

@@ -18,7 +18,7 @@ bodybincs: bodybin ac
 	cp bodybin bodybincs
 	./ac bodybincs
 
-bodybin: remload.asm
+bodybin: remload.asm code.asm
 	pasmo remload.asm bodybin
 
 ac: append_checksum.c

README.md

@@ -0,0 +1,11 @@
+# ZX Spectrum REM statement machine code loader
+
+Sometimes it would be useful to run machine code directly from ZX BASIC without having to load a CODE block or use lots of POKE and DATA statements. For example, you could add code for a fast loader or headerless loading block.
+
+This Makefile will generate a ZX BASIC .tap file with a REM statement containing the machine code, and will automatically run it. Simply amend the code in `code.asm` and run `make`. The file `program.tap` will be created which can be loaded in an emulator or real Spectrum.
+
+The included BASIC routine will CLEAR 59999 and set BORDER and PAPER to black and INK to white. Amend the `remload.asm` routine if this is not desired.
+
+## Requirements
+
+To use this, you need to install `make`, `pasmo`, `dd` and a C compiler.

code.asm

@@ -0,0 +1,12 @@
+; This is the main file you will edit to add your machine code to the REM statement.
+; You _must_ include the "entry_point" tag to point to the address which will called by the BASIC "PRINT USR" statement.
+; The default code below is for illustration only, and can be deleted.
+; But REMEMBER TO ADD THE entry_point TAG TO YOUR OWN CODE!
+
+
+data_start:		;if your routine starts here, move the entry_point tag here too
+	ld bc, 42
+	ret
+
+entry_point:		;move this tag to the start point of your code
+	jr data_start

remload.asm

@@ -45,7 +45,7 @@ printusr:
 	db "0"		;don't know if actual value is important
 	db #0e
 	db 0,0
-	dw code		;actual call to REM statement code
+	dw entry_point	;actual call to REM statement code
 	db 0
 	db ':'
 
@@ -53,8 +53,7 @@ remcode:
 	db #ea		;REM
 
 code:
-	ld bc, 42	;your code goes here
-	ret
+	INCLUDE code.asm
 
 enter:
 	db #0d