X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;ds=sidebyside;f=ROM2%2Fstart.s;h=c3f8d36f843ee6ed447d81233b4a60d5f5036ffc;hb=c0863797291ed5ab439e0d213cc26a2c62b00376;hp=15ce85571b136b2201469bbaf6f391f3199caab9;hpb=a56dcb7f2b7bf220f204223028e2e0c2c95b9097;p=uccvend-snackrom.git diff --git a/ROM2/start.s b/ROM2/start.s index 15ce855..c3f8d36 100644 --- a/ROM2/start.s +++ b/ROM2/start.s @@ -2,6 +2,14 @@ .globl _start _start: + ;; set port a to output + ldab #0xfc ; 11111000 + stab 0x1001 + + ;; start chiming + ldx #0x1000 + bset 00,x #0x10 + ;; enable the RTI ldaa #0x40 staa 0x1024 @@ -19,18 +27,22 @@ _start: staa 0x1030 ;; set the stack pointer - lds _stack + lds #_stack ;; blank initialised variables - should match memory.x's page0 ldx #0x0000 loop1: - cpx #0x0080 + cpx #0x0100 bcc out1 clr 00,x inx bra loop1 out1: + ;; stop chiming + ldx #0x1000 + bclr 00,x #0x10 + jsr main infinity: