Revising Makefiles and expanding README.

Makefile

@@ -0,0 +1,12 @@
+all:
+	cd common-post-process ; make ; cd ..
+	cd common ; make ; cd ..
+	cd emulator ; make ; cd ..
+
+run:
+	./emulator/emulator < common/system.obj
+
+clean:
+	cd common-post-process ; make clean ; cd ..
+	cd common ; make clean ; cd ..
+	cd emulator ; make clean ; cd ..

README.md

@@ -1,10 +1,45 @@
 # COMMON
-Advances some ideas using Steve Wozniak's SWEET16 interpreted byte-code language as inspiration. While the goal of SWEET16 was brevity, the goal of COMMON is functionality.
+Advances some ideas using Steve Wozniak's SWEET16 interpreted byte-code language as inspiration. While the goal of SWEET16 was brevity, the goal of COMMON is functionality. The intent is to make a platform suitable for many commercial, scientific, and engineering applications.
 
-To build and run:
+For example:
 
-    cd common-post-process ; make ; cp common-post-process ../common ; cd ..
-    cd common ; make ; cd ..
-    cd emulator ; make ; ./emulator < ../common/system.obj
+* native type is equivalent to fixed decimal ######.###
+* easier support for banked memory
+* easier support for higher language compilers
+* arithmetic operations add, subtract, multiply, divide, and modulus
+* inherent overflow/underflow detection
+* all control branching is relative and 16 bits, for easier relocatable code
+* support for custom functions, akin to INT in x86
 
-The makefiles use `re2c`, `flex`, `bison`, `gcc`, `cpp`, and `xa`.
+Why 6502 and not, for example, x86?
+
+* 6502 assembler is very easy and has a large archive of existing functions
+* existing 6502 SWEET16 does the "hard work"
+* interesting to see it run in newer versions of 6502 processors
+* how do you think Bender does what he does? (or the Terminator!)
+
+In progress:
+
+* add all the instructions (see `common/common.h` for the list)
+* a simple unit test suite to ensure each instruction is correct
+
+The meat of the project:
+
+* `common/common.h`: details of instructions
+* `common/common.asm`: defines the core instructions
+* `common/macros.h`: macros used to define the byte-code
+* `common/page6.src`: sample source file using the macros
+
+Auxiliary:
+
+* `emulator/*`: 6502 emulator (borrowed Mike Chambers' Fake6502 CPU emulator v1.1 ©2011)
+* `common-post-process/*`: this utility converts 32-bit fixed decimal quantities so that `xa` can use them
+
+Right now, for testing purposes, the code builds everything into one file `system.obj` and runs the code in the last block loaded, in this case, the code corresponding to `page6.src`. Eventually will support decoupling of system and application files.
+
+*To build and run:*
+
+    make
+    make run
+
+The makefiles use `re2c`, `flex`, `bison`, `gcc`, `cpp`, and `xa`. Will eventually support a `make install` which will install all of this.

common-post-process/Makefile

@@ -7,4 +7,4 @@ $(TGT): main.c $(TGT).h $(TGT).re $(TGT).l $(TGT).y
 	gcc main.c $(TGT).c $(TGT).tab.c $(TGT).yy.c -lfl -lm -o $(TGT)
 
 clean: 
-	rm -f $(TGT).c $(TGT).yy.h $(TGT).yy.c $(TGT).tab.h $(TGT).tab.c
+	rm -f $(TGT).c $(TGT).yy.h $(TGT).yy.c $(TGT).tab.h $(TGT).tab.c $(TGT)

common/Makefile

@@ -1,3 +1,5 @@
+POPR=../common-post-process/common-post-process
+
 system.obj: common.obj page6.obj
 	cat common.obj page6.obj > system.obj
 
@@ -5,8 +7,8 @@ common.obj: rom.h common.h common.asm
 	xa -M common.asm -l common.lbl -o common.obj
 
 page6.obj: rom.h macros.h page6.src
-	cpp -P page6.src | ./common-post-process > page6.asm
+	cpp -P page6.src | $(POPR) > page6.asm
 	xa -M page6.asm -l page6.lbl -o page6.obj
 
 clean: 
-	rm -f page6.asm common.obj page6.obj common.lbl page6.lbl
+	rm -f page6.asm common.obj page6.obj common.lbl page6.lbl system.obj

common/common.h

@@ -3,7 +3,8 @@
 
 ; Using four byte quantities aabbccdd with sign bit, overflow/underflow bit, 20 bits significand, 10 bits
 ; fraction. The quantity is valid if the overflow/underflow bit agrees with the sign bit. The intent is
-; to be able to recognize an overflow/underflow situation, rescale the arguments, and repeat.
+; to be able to recognize an overflow/underflow situation, rescale the arguments, and repeat the
+; calculation.
 
 ; Largest value:          $3fffffff or  1048575.999(9)
 ; Smallest value:         $c0000001 or -1048575.999(0)
@@ -136,6 +137,6 @@ _MNS_1	= %11111100	; i.e. the $FC part of $FFFFFC00
 
 ; masks for overflow and underflow
 _MSK_O	= %11000000	; mask for overflow
-_MSK_U	= %11000000	; mask for underflow
+_MSK_U	= %11000000	; mask for underflow - yes, the same!
 
 #endif /* __COMMON_H */

emulator/Makefile

@@ -1,3 +1,6 @@
 emulator: emulator.h emulator.c main.c
 	gcc -o emulator emulator.c main.c
 
+clean:
+	rm -f emulator
+