Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uwm.edu!linac!att!pacbell.com!tandem!zorch!amiga0!mykes From: mykes@amiga0.SF-Bay.ORG (Mike Schwartz) Newsgroups: comp.sys.amiga.programmer Subject: Re: Macro-68 Questions Message-ID: Date: 12 May 91 09:10:43 GMT References: <1991May8.205935.26761@unislc.uucp> Organization: Amiga makes it possible Lines: 51 In article <1991May8.205935.26761@unislc.uucp> ttobler@unislc.uucp (Trent Tobler) writes: >From article , by mykes@amiga0.SF-Bay.ORG (Mike Schwartz): > >>>2) Is bhs.s the same as bhi.s followed by beq.s? That is what >>> I assumed, bhs is not a true 68000 opcode in any case. >>> >> >> bhs.s means "branch higher or same" and it IS a true 68000 opcode. It >> is an unsigned branch while bge is signed. > >No, it is not a true 68000 opcode. The branching instructions are: > >Cond. >0000 BRA always >0001 --- used for the BSR instruction >0010 BHI C and Z clear >0011 BLS C or Z set >0100 BCC C clear >0101 BCS C set >0110 BNE Z clear >0111 BEQ Z set >1000 BVC V clear >1001 BVS V set >1010 BPL N clear >1011 BMI N set >1100 BGE N = V (ie both set or both clear) >1101 BLT N != B (ie one is set and one is clear) >1110 BGT Z clear, and N = V >1111 BLE Z set, and N != V > >> These are not anomalies, and you should find these "basic" features in any >> assembler you consider using. They were in the oldest Metacomco assembler >> available... > >So what do the assemblers do? Generate a BHI and BEQ sequence? > BHS is an alias for BCC. BLO is an alias for BCS. These are TRUE opcodes, meaning you don't need to make them from multiple instructions (like BHI BEQ). >- > Trent Tobler - ttobler@csulx.weber.edu -- **************************************************** * I want games that look like Shadow of the Beast * * but play like Leisure Suit Larry. * ****************************************************