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Happy new year all, The code below is part of a larger program and does not seem to be working. I am expecting it to loop to "busy" because the tested byte is not zero. The mask is 00000001 and the tested byte is 00000001, the program goes to "skip" instead. Help! org $c000 ldaa #%00000001 staa $c601 busy ldx $c600 BRCLR $0,x $1 skip jmp busy skip wai |
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BRCLR
Started by ●January 15, 2005
Reply by ●January 15, 20052005-01-15
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> -----Original Message----- > From: bal_gill21 [mailto:] > Sent: Saturday, January 15, 2005 1:57 PM > To: > Subject: [m68HC11] BRCLR > > Happy new year all, > The code below is part of a larger program and does not seem to be > working. I am expecting it to loop to "busy" because the tested byte > is not zero. The mask is 00000001 and the tested byte is 00000001, > the program goes to "skip" instead. Help! > > org $c000 > ldaa #%00000001 > staa $c601 > busy ldx $c600 <==== DID you mean IMMEDIATE? (As in point to $C600!) > BRCLR $0,x $1 skip > jmp busy > skip wai * | __O Thomas C. Sefranek |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, PL 74.4 http://hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org |
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Reply by ●January 15, 20052005-01-15
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No, i'm loading the contents of $c600 into x register. --- In , "Thomas Sefranek" <tcs@c...> wrote: > > > > -----Original Message----- > > From: bal_gill21 [mailto:bal_gill21@y...] > > Sent: Saturday, January 15, 2005 1:57 PM > > To: > > Subject: [m68HC11] BRCLR > > > > Happy new year all, > > The code below is part of a larger program and does not seem to be > > working. I am expecting it to loop to "busy" because the tested byte > > is not zero. The mask is 00000001 and the tested byte is 00000001, > > the program goes to "skip" instead. Help! > > > > org $c000 > > ldaa #%00000001 > > staa $c601 > > busy ldx $c600 <==== DID you mean IMMEDIATE? (As in point to $C600!) > > BRCLR $0,x $1 skip > > jmp busy > > skip wai > > > > > > * > | __O Thomas C. Sefranek WA1RHP@A... > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, PL 74.4 > > http://hamradio.cmcorp.com/inventory/Inventory.html > http://www.harvardrepeater.org |
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Reply by ●January 15, 20052005-01-15
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> -----Original Message----- > From: bal_gill21 [mailto:] > Sent: Saturday, January 15, 2005 2:30 PM > To: > Subject: [m68HC11] Re: BRCLR > > No, i'm loading the contents of $c600 into x register. O.K. I'm missing something here... Your putting a ONE in the LSB of the address of X. (The contents of $C600 MSB is undefined, AND $C601 is a 1.) So X is pointing... who knows where.. and your Testing the location X is pointing to for it to be clear... A few comments in your code to explain what you MEANT to do would help. > * | __O Thomas C. Sefranek |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, PL 74.4 http://hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org |
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Reply by ●January 15, 20052005-01-15
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org $c000 ldaa #%00000001 staa $c601 busy ldx $c600 ;line 4 BRCLR $0,x $1 skip ;line 5 jmp busy skip wai line 4: I have put $c600 here because its going into the X register, so $c600 has nothing in it ie 00000000. $c601 has a $1 in it ie 00000001. When it's loaded into the x register it looks like :0000000000000001. line 5: I want it to check if the very last bit in x reg (1) is a 1 or 0 and jump accordingly. If the last bit is 0 I want it to go to "skip" and "busy" if its a 1. --- In , "Thomas Sefranek" <tcs@c...> wrote: > > -----Original Message----- > > From: bal_gill21 [mailto:bal_gill21@y...] > > Sent: Saturday, January 15, 2005 2:30 PM > > To: > > Subject: [m68HC11] Re: BRCLR > > > > No, i'm loading the contents of $c600 into x register. > > O.K. I'm missing something here... > > Your putting a ONE in the LSB of the address of X. (The contents of $C600 > MSB is undefined, AND $C601 is a 1.) So X is pointing... who knows where.. > and your Testing the location X is pointing to for it to be clear... > > A few comments in your code to explain what you MEANT to do would help. > > > * > | __O Thomas C. Sefranek WA1RHP@A... > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, PL 74.4 > > http://hamradio.cmcorp.com/inventory/Inventory.html > http://www.harvardrepeater.org |
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Reply by ●January 15, 20052005-01-15
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Ahhh! You CAN NOT test the last bit in an INDEX register. You can only test DATA registers. In other words you can test the bits of a byte that the INDEX is pointing to. You could (And it's still not clear WHY you want to bit test the index,) Copy the index to 2 data registers and test the effective shadow of the index. * | __O Thomas C. Sefranek |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, PL 74.4 http://hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org > -----Original Message----- > From: bal_gill21 [mailto:] > Sent: Saturday, January 15, 2005 2:55 PM > To: > Subject: [m68HC11] Re: BRCLR > > org $c000 > ldaa #%00000001 > staa $c601 > busy ldx $c600 ;line 4 > BRCLR $0,x $1 skip ;line 5 > jmp busy > skip wai > > line 4: I have put $c600 here because its going into the X register, > so $c600 has nothing in it ie 00000000. $c601 has a $1 in it ie > 00000001. When it's loaded into the x register it looks > like :0000000000000001. > > line 5: I want it to check if the very last bit in x reg (1) is a 1 > or 0 and jump accordingly. If the last bit is 0 I want it to go > to "skip" and "busy" if its a 1. > > --- In , "Thomas Sefranek" <tcs@c...> wrote: > > > > > > > > > -----Original Message----- > > > From: bal_gill21 [mailto:bal_gill21@y...] > > > Sent: Saturday, January 15, 2005 2:30 PM > > > To: > > > Subject: [m68HC11] Re: BRCLR > > > > > > No, i'm loading the contents of $c600 into x register. > > > > O.K. I'm missing something here... > > > > Your putting a ONE in the LSB of the address of X. (The contents of > $C600 > > MSB is undefined, AND $C601 is a 1.) So X is pointing... who knows > where.. > > and your Testing the location X is pointing to for it to be clear... > > > > A few comments in your code to explain what you MEANT to do would > help. > > > > > * > > | __O Thomas C. Sefranek WA1RHP@A... > > |_-\<,_ Amateur Radio Operator: WA1RHP > > (*)/ (*) Bicycle mobile on 145.41, PL 74.4 > > > > http://hamradio.cmcorp.com/inventory/Inventory.html > > http://www.harvardrepeater.org > > Yahoo! Groups Links > |
Reply by ●January 15, 20052005-01-15
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At line 5>>>BRCLR $0,x $1 skip <<< the lower byte of the x
register contains the contents of $c600. The BRCLR instruction interrupts the contents of x as an address. The LSB of this address is tested. This is not what you intend to be doing. See my note below. Nick -----Original Message----- From: bal_gill21 [mailto:] Sent: Saturday, January 15, 2005 2:55 PM To: Subject: [m68HC11] Re: BRCLR org $c000 ldaa #%00000001 staa $c601 busy ldx $c600 ;line 4 <contents of $c600 to the X register which are undefined BRCLR $0,x $1 skip ;line 5 jmp busy skip wai line 4: I have put $c600 here because its going into the X register, so $c600 has nothing in it ie 00000000. $c601 has a $1 in it ie 00000001. Nick's Note:.............................. " When it's loaded into the x register it looks like :0000000000000001." So, the byte located in RAM at $0001 is being tested. line 5: I want it to check if the very last bit in x reg (1) is a 1 or 0 and jump accordingly. If the last bit is 0 I want it to go to "skip" and "busy" if its a 1. --- In , "Thomas Sefranek" <tcs@c...> wrote: > > -----Original Message----- > > From: bal_gill21 [mailto:bal_gill21@y...] > > Sent: Saturday, January 15, 2005 2:30 PM > > To: > > Subject: [m68HC11] Re: BRCLR > > > > No, i'm loading the contents of $c600 into x register. > > O.K. I'm missing something here... > > Your putting a ONE in the LSB of the address of X. (The contents of $C600 > MSB is undefined, AND $C601 is a 1.) So X is pointing... who knows where.. > and your Testing the location X is pointing to for it to be clear... > > A few comments in your code to explain what you MEANT to do would help. > > > * > | __O Thomas C. Sefranek WA1RHP@A... > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, PL 74.4 > > http://hamradio.cmcorp.com/inventory/Inventory.html > http://www.harvardrepeater.org Yahoo! Groups Links |
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Reply by ●January 16, 20052005-01-16
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My earlier Email was not accurate. "interrupts" should have
been "interpret". I have also added more of an explanation. Delete that Email and use this one. Sorry about that. -----Original Message----- From: Nick Reitter [mailto:] Sent: Saturday, January 15, 2005 7:08 PM To: Subject: RE: [m68HC11] Re: BRCLR At line 5>>>BRCLR $0,x $1 skip <<< the lower byte of the x register contains the contents of $c600. The BRCLR instruction interprets the contents of x as an address. The x register is a pointer register. Pointing to the location of the bit(s) to be tested. The LSB at this address is tested. This is not what you intend to do. Also, see my note below. Nick -----Original Message----- From: bal_gill21 [mailto:] Sent: Saturday, January 15, 2005 2:55 PM To: Subject: [m68HC11] Re: BRCLR org $c000 ldaa #%00000001 staa $c601 busy ldx $c600 ;line 4 <contents of $c600 to the X register which are undefined BRCLR $0,x $1 skip ;line 5 jmp busy skip wai line 4: I have put $c600 here because its going into the X register, so $c600 has nothing in it ie 00000000. $c601 has a $1 in it ie 00000001. Nick's Note:.............................. " When it's loaded into the x register it looks like :0000000000000001." So, the x register is pointing to the byte located in RAM at $0001. The LSB at this location in RAM is being tested. line 5: I want it to check if the very last bit in x reg (1) is a 1 or 0 and jump accordingly. If the last bit is 0 I want it to go to "skip" and "busy" if its a 1. --- In , "Thomas Sefranek" <tcs@c...> wrote: > > -----Original Message----- > > From: bal_gill21 [mailto:bal_gill21@y...] > > Sent: Saturday, January 15, 2005 2:30 PM > > To: > > Subject: [m68HC11] Re: BRCLR > > > > No, i'm loading the contents of $c600 into x register. > > O.K. I'm missing something here... > > Your putting a ONE in the LSB of the address of X. (The contents of $C600 > MSB is undefined, AND $C601 is a 1.) So X is pointing... who knows where.. > and your Testing the location X is pointing to for it to be clear... > > A few comments in your code to explain what you MEANT to do would help. > > > * > | __O Thomas C. Sefranek WA1RHP@A... > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, PL 74.4 > > http://hamradio.cmcorp.com/inventory/Inventory.html > http://www.harvardrepeater.org Yahoo! Groups Links Yahoo! Groups Links |
