invalid_msg: .asciz "Invalid instruction at %X\n" .global _m68k_invalid _m68k_invalid: push %ecx push invalid_msg xor %eax, %eax call _printf push $1 call _exit .global _bcd_add _bcd_add: xchg %eax, %edi mov %cl, %ch mov %al, %ah and $0xF, %ch and $0xF, %ah and $0xF0, %cl and $0xF0, %al add %ah, %ch cmp $10, %ch jb no_adjust add $6, %ch no_adjust: add %ch, %al add %al, %cl mov $0, %ch jc def_adjust cmp $0xA0, %cl jb no_adjust_h def_adjust: add $0x60, %cl mov $1, %ch no_adjust_h: mov %edi, %eax ret .global _bcd_sub _bcd_sub: xchg %eax, %edi mov %cl, %ch mov %al, %ah and $0xF, %ch and $0xF, %ah and $0xF0, %cl and $0xF0, %al sub %ah, %ch cmp $10, %ch jb no_adjusts sub $6, %ch no_adjusts: add %ch, %cl sub %al, %cl mov $0, %ch jc def_adjusts cmp $0xA0, %cl jb no_adjust_hs def_adjusts: sub $0x60, %cl mov $1, %ch no_adjust_hs: mov %edi, %eax ret