insn_set_v2.txt

All registers are 16 bits and are initialized to all zeros.
Registers: pc, sp, fp, ax, bx, cx, dx, ex
pc (000): program counter
sp (001): stack pointer
fp (010): frame pointer
ax (011): general purpose A
bx (100): general purpose B
cx (101): general purpose C
dx (110): general purpose D
ex (111): general purpose E

All instructions are 16 bits.
Big R is r1, little r is r2, big G is r3, little c is 8-bit immediate in bit encodings.
PC is incremented after each instruction except when PC is written to during its execution (branches, etc.)
(add  r1 c)        0b00000RRRcccccccc         R1 += C
(andl r1 c)        0b00001RRRcccccccc         R1[7:0] &= C
(andh r1 c)        0b00010RRRcccccccc         R1[15:8] &= C
(orl  r1 c)        0b00011RRRcccccccc         R1[7:0] |= C
(orh  r1 c)        0b00100RRRcccccccc         R1[15:8] |= C
(movl r1 c)        0b00101RRRcccccccc         R1[7:0] = C
(movh r1 c)        0b00110RRRcccccccc         R1[15:8] = C
(brnz r1 c)        0b00111RRRcccccccc         if(R1 != 0) PC += C
(not  r1 r2)       0b01000RRRrrrxxxxx         R1 = ~R2
(add  r1 r2 r3)    0b01001RRRrrrGGGxx         R1 = R2 + R3
(and  r1 r2 r3)    0b01010RRRrrrGGGxx         R1 = R2 & R3
(or   r1 r2 r3)    0b01011RRRrrrGGGxx         R1 = R2 | R3
(mov (@+ r1 c) r2) 0b10RRRrrrcccccccc         *(R1 + C) = R2
(mov r1 (@+ r2 c)) 0b11RRRrrrcccccccc         R1 = *(R2 + C)

All memory locations are 16 bits wide.
0x0000 - 0x1fff   8Kword ROM (program/constant storage)
         0x2000   Input pins
         0x2001   Output pins
0xf000 - 0xffff   4Kword RAM (volatile program/data storage)

Assembler directives begin with the . character and are case insensitive.
The special symbol @ equals the current address that is being assembled into.
(.align N)         Align the following code to the 2^N word boundary (increment @ until 2^N LSBs are zero).
(.ascii "text")    Emit the null-terminated string given. Each word contains 2 characters, and the result must be word aligned.
(.word C N)        Emit the word C, N times.
(.if symbol)       If symbol is not defined or zero, disable emission.
(.else)            If emission is enabled, disable emission. If emission is disabled, enable emission.
(.endif)           Enable emission.
(.include "file")  If the file given exists and is readable, assemble the file at the current location.
(.macro name)      Disable emission and start defining a macro (name). name must be unique among other macros and opcodes.
                   Within the macro, use the symbol $N to denote the Nth positional argument to the macro.
(.endmacro)        Stop defining a macro and enable emission. The macro can be invoked using (name arg1 arg2 ...).
(.print "text")    Print the null-terminated string given to the standard output.
(.set symbol C)    Define or set the value of the given symbol to the given word C.
(.label label)     Equivalent to (.set label @).