6502.org

Code: Select all

function1(1, 2, function2(3, 4));

Code: Select all

function1(1, 2, function1(3, 4))

Code: Select all

function address + 0: JMP *+sizeof(parameters+return values+locals)
function address + 3: parameters
function address + 3 + sizeof(parameters): return values
function address + 3 + sizeof(parameters + return values) : locals
function address + 3 + sizeof(parameters + return values + locals) : function code

Code: Select all

"function address": parameters
"function address" + sizeof(parameters): return values
"function address" + sizeof(parameters + return values) : locals
"function address" + sizeof(parameters + return values + locals) : function entry point

Code: Select all

"function address": parameters
"function address" + sizeof(parameters): return values
function address" + sizeof(parameters + return values) : function entry point
<code>
"function address" + sizeof(parameters + return values + code) : locals

Code: Select all

JSR func1
params:
param1 DW 0
param2 DW 0
retvals:
retval1 DW 0
... continue code

Code: Select all

sub Expr2Simple(sop: uint8, uop: uint8, lhs: [Node], rhs: [Node]): (result: [Node])
	ResolveUntypedConstantsNeedingNumbers(lhs, rhs);
	var op := uop;
	if IsSNum(lhs.type) != 0 then
		op := sop;
	end if;

	var ltype := lhs.type;
	result := MidC2Op(op, NodeWidth(lhs), lhs, rhs);
	result.type := ltype;
end sub;

Code: Select all

        ; Expr2Simple
f563_Expr2Simple:
        sta ws1+79      ; unmarshal rhs into a variable (passed in xa)
        stx ws1+80
        plx                 ; remove return address from the stack
        pla 
        inx 
        stx c21_0fce   ; poke into return instruction
        sta c21_0fce+1
        ldy #3             ; unmarshal node, uop and sop together
c21_0fcf:
        pla 
        sta ws1+75,y
        dey 
        bpl c21_0fcf

        lda ws1+77 ; marshal lhs onto the stack
        ldx ws1+78
        pha 
        phx 
        lda ws1+79 ; marshal rhs into xa
        ldx ws1+80
        ajsr f556_ResolveUntypedConstantsNeedingNumbers

        lda ws1+76 ; copy uop to sop
        sta ws1+83

        ldy #8
        lda (ws1+77),y ; lhs.type high byte into x
        tax 
        dey 
        lda (ws1+77),y ; lhs.type low byte into a giving xa
        ajsr f238_IsSNum ; returns result in a
        tax                    ; set flag bytes
        beq c21_0fd4

c21_0fd3:

        lda ws1+75      ; op := sop
        sta ws1+83

        bra c21_0fd0

c21_0fd4:

c21_0fd0:

        ldy #8                ; read lhs.type again. Huh, I should move this up
        lda (ws1+77),y
        tax 
        dey 
        lda (ws1+77),y
        sta ws1+84
        stx ws1+85

        lda ws1+83      ; marshal op for call to MidC2Op
        pha 
        lda ws1+77     ; marshal lhs into xa for call to NodeWidth
        ldx ws1+78
        ajsr f178_NodeWidth ; returns result in a
        pha                ; marshal for call to MidC2Op
        lda ws1+77    ; marshal LHS
        ldx ws1+78
        pha 
        phx 
        lda ws1+79    ; marshal RHS
        ldx ws1+80
        ajsr f186_MidC2Op
        sta ws1+81
        stx ws1+82    ; result in xa

        lda ws1+84    ; write ltype to result.type
        ldx ws1+85
        ldy #7
        sta (ws1+81),y
        txa 
        iny 
        sta (ws1+81),y

        lda ws1+81    ; marshal result into xa for return
        ldx ws1+82
c21_0fce=*+1
        jmp $ffff     ; jumps to return address

Code: Select all

void strcpy(char* a, const char* b)
{
    while(*a++ = *b++)
        ;
}

Code: Select all

T_EXPR: integer constant, variable or function
        emit { TOK_BYTE } E_NUMBER_BYTE
        emit { TOK_NUM } E_NUMBER_WORD
        "-" T_EXPR emit { TOK_NEG }
        "+" T_EXPR
        "NOT" NOT_EXPR emit { TOK_L_NOT }
        ARRAY_WORD_ADDR emit { TOK_DPEEK }
        ARRAY_BYTE_ADDR emit { TOK_PEEK }
        emit { TOK_VAR_LOAD } E_VAR_WORD
        PAR_EXPR

Code: Select all

# Code for   B = A(X+1)
 VAR_LOAD A
 PUSH
 VAR_LOAD X
 PUSH
 LOAD_BYTE  #1
 ADD
 USHL
 ADD
 DPEEK
 VAR_STORE B
 

Code: Select all

 LOAD_1
 ADD_VAR X
 USHL
 ADD_VAR A
 DPEEK
 VAR_STORE B

Code: Select all

 LDA #1
 LDX #0

 CLC
 ADC VAR_X
 PHA
 TXA
 ADC VAR_X+1
 TAX
 PLA

 ASL
 PHA
 TXA
 ASL
 TAX
 PLA

 CLC
 ADC VAR_A
 PHA
 TXA
 ADC VAR_A+1
 TAX
 PLA

 STA  PTR
 STX  PTR+1
 LDY  #1
 LDA (PTR), Y
 TAX
 DEY
 LDA (PTR), Y

 STA VAR_B
 STX VAR_B+1