%option no_symbol_prefixing, ignore_unused

; Tiny syslib for minimalistic programs that can run on a C64

%import shared_sys_functions

sys {
    extsub $FFD2 = CHROUT(ubyte character @ A)           ; output a character

    ; these push/pop routines are always required by the compiler:

    asmsub reset_system()  {
        ; Soft-reset the system back to initial power-on Basic prompt.
        %asm {{
            sei
            lda  #14
            sta  $01        ; bank the kernal in
            jmp  ($fffc)    ; reset vector
        }}
    }

    asmsub exit(ubyte returnvalue @A) {
        ; -- immediately exit the program with a return code in the A register
        %asm {{
            sta  p8_sys_startup.cleanup_at_exit._exitcode
            ldx  prog8_lib.orig_stackpointer
            txs
            jmp  p8_sys_startup.cleanup_at_exit
        }}
    }

    asmsub exit2(ubyte resulta @A, ubyte resultx @X, ubyte resulty @Y) {
        ; -- immediately exit the program with result values in the A, X and Y registers.
        %asm {{
            sta  p8_sys_startup.cleanup_at_exit._exitcode
            stx  p8_sys_startup.cleanup_at_exit._exitcodeX
            sty  p8_sys_startup.cleanup_at_exit._exitcodeY
            ldx  prog8_lib.orig_stackpointer
            txs
            jmp  p8_sys_startup.cleanup_at_exit
        }}
    }

    asmsub exit3(ubyte resulta @A, ubyte resultx @X, ubyte resulty @Y, bool carry @Pc) {
        ; -- immediately exit the program with result values in the A, X and Y registers, and the Carry flag in the status register.
        %asm {{
            sta  p8_sys_startup.cleanup_at_exit._exitcode
            lda  #0
            rol  a
            sta  p8_sys_startup.cleanup_at_exit._exitcarry
            stx  p8_sys_startup.cleanup_at_exit._exitcodeX
            sty  p8_sys_startup.cleanup_at_exit._exitcodeY
            ldx  prog8_lib.orig_stackpointer
            txs
            jmp  p8_sys_startup.cleanup_at_exit
        }}
    }
}


p8_sys_startup {
    %option force_output

    asmsub  init_system() {
        %asm {{
            rts
        }}
    }

    asmsub  init_system_phase2() {
        %asm {{
            rts
        }}
    }

    asmsub  cleanup_at_exit() {
        ; executed when the main subroutine does rts
        %asm {{
            lda  _exitcarry
            lsr  a
            lda  _exitcode
            ldx  _exitcodeX
            ldy  _exitcodeY
            rts

            .section BSS
_exitcarry  .byte ?
_exitcode   .byte ?
_exitcodeX  .byte ?
_exitcodeY  .byte ?
            .send BSS

            ; !notreached!
        }}
    }
}


cx16 {
    ; the sixteen virtual 16-bit registers that the CX16 has defined in the zeropage
    ; they are simulated on the C64 as well but their location in memory is different
    ; (because there's no room for them in the zeropage in the default configuration)
    ; Note that when using ZP options that free up more of the zeropage (such as %zeropage kernalsafe)
    ; there might be enough space to put them there after all, and the compiler will change these addresses!
    &uword r0  = $cfe0
    &uword r1  = $cfe2
    &uword r2  = $cfe4
    &uword r3  = $cfe6
    &uword r4  = $cfe8
    &uword r5  = $cfea
    &uword r6  = $cfec
    &uword r7  = $cfee
    &uword r8  = $cff0
    &uword r9  = $cff2
    &uword r10 = $cff4
    &uword r11 = $cff6
    &uword r12 = $cff8
    &uword r13 = $cffa
    &uword r14 = $cffc
    &uword r15 = $cffe

    ; signed word versions
    &word r0s  = $cfe0
    &word r1s  = $cfe2
    &word r2s  = $cfe4
    &word r3s  = $cfe6
    &word r4s  = $cfe8
    &word r5s  = $cfea
    &word r6s  = $cfec
    &word r7s  = $cfee
    &word r8s  = $cff0
    &word r9s  = $cff2
    &word r10s = $cff4
    &word r11s = $cff6
    &word r12s = $cff8
    &word r13s = $cffa
    &word r14s = $cffc
    &word r15s = $cffe

    ; signed long versions
    &long r0r1sl  = $cfe0
    &long r2r3sl  = $cfe4
    &long r4r5sl  = $cfe8
    &long r6r7sl  = $cfec
    &long r8r9sl  = $cff0
    &long r10r11sl = $cff4
    &long r12r13sl = $cff8
    &long r14r15sl = $cffc

    ; ubyte versions (low and high bytes)
    &ubyte r0L  = $cfe0
    &ubyte r1L  = $cfe2
    &ubyte r2L  = $cfe4
    &ubyte r3L  = $cfe6
    &ubyte r4L  = $cfe8
    &ubyte r5L  = $cfea
    &ubyte r6L  = $cfec
    &ubyte r7L  = $cfee
    &ubyte r8L  = $cff0
    &ubyte r9L  = $cff2
    &ubyte r10L = $cff4
    &ubyte r11L = $cff6
    &ubyte r12L = $cff8
    &ubyte r13L = $cffa
    &ubyte r14L = $cffc
    &ubyte r15L = $cffe

    &ubyte r0H  = $cfe1
    &ubyte r1H  = $cfe3
    &ubyte r2H  = $cfe5
    &ubyte r3H  = $cfe7
    &ubyte r4H  = $cfe9
    &ubyte r5H  = $cfeb
    &ubyte r6H  = $cfed
    &ubyte r7H  = $cfef
    &ubyte r8H  = $cff1
    &ubyte r9H  = $cff3
    &ubyte r10H = $cff5
    &ubyte r11H = $cff7
    &ubyte r12H = $cff9
    &ubyte r13H = $cffb
    &ubyte r14H = $cffd
    &ubyte r15H = $cfff

    ; signed byte versions (low and high bytes)
    &byte r0sL  = $cfe0
    &byte r1sL  = $cfe2
    &byte r2sL  = $cfe4
    &byte r3sL  = $cfe6
    &byte r4sL  = $cfe8
    &byte r5sL  = $cfea
    &byte r6sL  = $cfec
    &byte r7sL  = $cfee
    &byte r8sL  = $cff0
    &byte r9sL  = $cff2
    &byte r10sL = $cff4
    &byte r11sL = $cff6
    &byte r12sL = $cff8
    &byte r13sL = $cffa
    &byte r14sL = $cffc
    &byte r15sL = $cffe

    &byte r0sH  = $cfe1
    &byte r1sH  = $cfe3
    &byte r2sH  = $cfe5
    &byte r3sH  = $cfe7
    &byte r4sH  = $cfe9
    &byte r5sH  = $cfeb
    &byte r6sH  = $cfed
    &byte r7sH  = $cfef
    &byte r8sH  = $cff1
    &byte r9sH  = $cff3
    &byte r10sH = $cff5
    &byte r11sH = $cff7
    &byte r12sH = $cff9
    &byte r13sH = $cffb
    &byte r14sH = $cffd
    &byte r15sH = $cfff

    ; boolean versions
    &bool r0bL  = $cfe0
    &bool r1bL  = $cfe2
    &bool r2bL  = $cfe4
    &bool r3bL  = $cfe6
    &bool r4bL  = $cfe8
    &bool r5bL  = $cfea
    &bool r6bL  = $cfec
    &bool r7bL  = $cfee
    &bool r8bL  = $cff0
    &bool r9bL  = $cff2
    &bool r10bL = $cff4
    &bool r11bL = $cff6
    &bool r12bL = $cff8
    &bool r13bL = $cffa
    &bool r14bL = $cffc
    &bool r15bL = $cffe

    &bool r0bH  = $cfe1
    &bool r1bH  = $cfe3
    &bool r2bH  = $cfe5
    &bool r3bH  = $cfe7
    &bool r4bH  = $cfe9
    &bool r5bH  = $cfeb
    &bool r6bH  = $cfed
    &bool r7bH  = $cfef
    &bool r8bH  = $cff1
    &bool r9bH  = $cff3
    &bool r10bH = $cff5
    &bool r11bH = $cff7
    &bool r12bH = $cff9
    &bool r13bH = $cffb
    &bool r14bH = $cffd
    &bool r15bH = $cfff
}