README.8070

Differences from the reference 8070 instruction set

.word not .dbyte (TO FIX)
No X`FF etc but 0xFF syntax is used (probably WONTFIX)
#nn is supported for constants as well as =nn
The use of $ in a symbol is not a good idea
Expressions are more limited (TODO one day)
Lowercase is used
Need to add .ADDR (writes value - 1)


Notes:

Although similar to the 8060 the assembly language format changes totally

We split them up as

Implicit		
	NOP
	RET
	SSM

imm16
	JSR	(PLI 0, addr)
	JMP	(LDI 0) 

p,imm16
	PLI

logic8
	AND XOR (no S) OR

	A,E
	A,=const
	S,=const (status)
	A, memory

logic16 ADD SUB

	A,E
	A,=const
	EA,=const
	A, @disp,r disp,@r , disp,r label (actually PC rel)
	EA, ""
	A, label (0xFFxx) .dp
	EA, label (0xFFxx)


mem8	DLD ILD

	dld memory
	dld 0xffxx

Branches

	disp,r
	label (implies disp,pc)

Swaps (both ways around allowed)
	XCH A,E
	XCH E,A
	XCH EA,Pn
	XCH Pn,EA


Weird

	CALL

EA/T
	DIV EA,T
	MPY EA,T

Loads
	E,A
	S,A
	A,S
	A,E
	r,EA
	T,EA
	A,=const8
	EA,=const16
	Pn,=const16
	T,=const16
	A,mem
	EA,mem
	T,m
	A,0xFFxx
	EA,0xFFxx
	T,0xFFxx
	EA,Pn
	EA,T

Stores
	A,mem
	A,0xffxx
	EA,mem
	EA,0xffxx

A only
	RR
	RRL
	SRL
	
A/EA
	SL	A
	SR	A
	SL	EA
	SR	EA

Pop	POP/PUSH	These have equivalent LD/ST representations
			but are unique instructions not aliases

	A
	EA
	Pn (not P1, P0 is RET)

	A
	EA
	Pn (not P1)

Syntax
	:n		direct page.
	=n		constant (also support #n I think)
	n,Pn		offset (Pn, SP, PC)
	@n,Pn		autoindex (--Pn Pn++)
	Pn,@n		"" implies reverse sign

There is no automatic recognition of FFxx as direct page at this point, as
the classic assembler does because we have an actual linker so addresses
are unknown.

We accept the non alias versions of some instructions. So LD P0,=n (JMP) is
permitted as is PLI P0,=n (JSR) and POP P0 (RET)

BZ and BNZ are supported as JZ and JNZ for extension. BRA will extend to JMP
when necessary. The BP and BND have no inverses. There is no test for CC and
other flags. This is architectural. Instead LD A,S AND A,=n then BZ/BNZ.
Likewise things like "clear carry" are done with AND/OR S,=n