Re: Who remembers about the floating point calculator?
On 1 Feb 2009, at 13:00, Frode Tennebø wrote: On Saturday 31. January 2009, Andrew Collier wrote: Hi, AS you may know, if you CALL a machine code routine with some parameters, they are pushed onto the ROM's floating point calculator stack. I'm trying to use this, but having some difficulty getting the numbers back out again. Can anyone spot what's going wrong? Since no one else has come to the rescue I'll give it a shot from 20 years old memory. The sequence seems right at first glance, I would therefore look at something external. first thing to check is that you are not using bank D and that interrupts are disabled. Then check that it is indeed 32768 and 81920 which are stored on the stack initially. Hi, Thanks, I've found the problem now. What I'd forgotten was that you get two FPC stack entries for each parameter - the first describes the type (which allows for CALL statements with string arguments) and this is what was coming out as 0xc0 every time. Cheers, Andrew -- --- Andrew Collier http://www.intensity.org.uk/ --- --
Re: Who remembers about the floating point calculator?
On Saturday 31. January 2009, Andrew Collier wrote: > Hi, > > AS you may know, if you CALL a machine code routine with some > parameters, they are pushed onto the ROM's floating point calculator > stack. I'm trying to use this, but having some difficulty getting the > numbers back out again. Can anyone spot what's going wrong? Since no one else has come to the rescue I'll give it a shot from 20 years old memory. The sequence seems right at first glance, I would therefore look at something external. first thing to check is that you are not using bank D and that interrupts are disabled. Then check that it is indeed 32768 and 81920 which are stored on the stack initially. Sorry if this seems obvious, but without knowing more I'm just guessing here. -Frode -- ^ Frode Tennebø | email: fr...@tennebo.com | fr...@irc ^ | with Standard.Disclaimer; use Standard.Disclaimer; |
Who remembers about the floating point calculator?
Hi, AS you may know, if you CALL a machine code routine with some parameters, they are pushed onto the ROM's floating point calculator stack. I'm trying to use this, but having some difficulty getting the numbers back out again. Can anyone spot what's going wrong? Consider a routine taking two parameters, which I'll designate FROM and TO; each are addresses in BASIC format (i.e. between 16384 and 540671) - I want to separate these into a (page+1) and offset of each address, and collect the resulting 16-bit values using JGETINT. If I call the following routine with CALL (address), 32768, 81920 then the values which are returned in HL from the calls to JGETINT are, in order: 0x ; fine, 81920 mod 16384 == 0 0x0005 ; fine, 82910 div 16384 == 5 0x00c0 ; wrong - expect 32768 mode 16384 == 0 0x ; wrong - expect 32768 mode 16384 == 2 Are there any entry conditions to 0x28 or JGETINT which I need to obey and have forgotten about? Have I got the FPC sequence wrong? Thanks in advance for any useful observations, Andrew ENTRY: cp 2 jp nz, parameter_error rst 0x28 ; call floating point calculator, stack = FR,TO db 0x25 ; DUP ; FR,TO,TO db 0xe2 ; STK16K; FR,TO,TO,16K db 0x08 ; MOD ; FR,TO,TO\16K db 0x06 ; SWOP ; FR,TO\16K,TO db 0xe2 ; STK16K; FR,TO\16K,TO,16K db 0x09 ; IDIV ; FR,TO\16K,TO/16K db 0x1c ; SWOP13; TO/16K,TO\16K,FR db 0x25 ; DUP ; TO/16K,TO\16K,FR,FR db 0xe2 ; STK16K; TO/16K,TO\16K,FR,FR,16K db 0x08 ; MOD ; TO/16K,TO\16K,FR,FR\16K db 0x06 ; SWOP ; TO/16K,TO\16K,FR\16K,FR db 0xe2 ; STK16K; TO/16K,TO\16K,FR\16K,FR,16K db 0x09 ; IDIV ; TO/16K,TO\16K,FR\16K,FR/16K db 0x06 ; SWOP ; TO/16K,TO\16K,FR/16K,FR\16K db 0x33 ; EXIT call JGETINT ld (FROM_os),hl call JGETINT ld a,h or a jr nz, invalid_argument_error ld a,l dec a cp 32 jr nc, invalid_argument_error ld (FROM_page),a call JGETINT ld (TO_os),hl call JGETINT ld a,h or a jr nz, invalid_argument_error ld a,l dec a cp 32 jr nc, invalid_argument_error ld (TO_page),a -- --- Andrew Collier http://www.intensity.org.uk/ --- --
