<ACPS2924@Ryerson.Ca> (01/27/91)
Is it possible in MSC 5.1 to gain access to the registers directly. Turbo C has the _AX,_BX... pseudo-variables for them is this possible in MSC and if so HOW??? Peter ACPS2924@ryerson.ca
resnicks@netcom.UUCP (Steve Resnick) (01/30/91)
In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes: >Is it possible in MSC 5.1 to gain access to the registers directly. >Turbo C has the _AX,_BX... pseudo-variables for them >is this possible in MSC and if so HOW??? Nope. I believe MSC 6.0 supports this, but I am not sure.... Cheers! Steve -- ------------------------------------------------------------------------------- resnicks@netcom.com, apple!camphq!105!steve.resnick, IFNA: 1:143/105.0, USNail: 530 Lawrence Expressway, Suite 374 Sunnyvale, Ca 94086 - In real life: Steve Resnick. Flames, grammar and spelling errors >/dev/null 0x2b |~ 0x2b, THAT is the question. -------------------------------------------------------------------------------
nengle@copper.ucs.indiana.edu (nathan engle) (01/30/91)
In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes: >Is it possible in MSC 5.1 to gain access to the registers directly. >Turbo C has the _AX,_BX... pseudo-variables for them >is this possible in MSC and if so HOW??? > > >Peter >ACPS2924@ryerson.ca Not directly from 5.1. Whenever I needed to get at my registers in 5.1 I would drop into assembler. There's a neat little microcontroller from NEC called the V25 which is code compatible with the V20, and which WILL allow you to access register contents directly. The '25 actually has 8 sets of registers which can be addressed either normally as registers or they can also be mapped as memory locations (so you would find the contents of a register by reading a memory location - SLOW but it works). Direct access to the registers is much simpler in MSC6.0 using the inline assembler. I don't think that there are C constructs for referring to the registers, but I had never seen that as a problem. Direct access to registers just means more reserved words and more rope to hang yourself with (as if C programmers needed any more). What exactly are you trying to accomplish? Nathan Engle Software Evangelist Indiana University Dept of Psychology nengle@copper.ucs.indiana.edu
prk@planet.bt.co.uk (Peter Knight) (01/30/91)
ACPS2924@Ryerson.Ca writes: >Is it possible in MSC 5.1 to gain access to the registers directly. >Turbo C has the _AX,_BX... pseudo-variables for them >is this possible in MSC and if so HOW??? NO ! Peter Knight BT Research #include <std.disclaimer>
jvb7u@fermi.clas.Virginia.EDU (Jon Brinkmann) (01/31/91)
In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes:
#Is it possible in MSC 5.1 to gain access to the registers directly.
#Turbo C has the _AX,_BX... pseudo-variables for them
#is this possible in MSC and if so HOW???
The variables _AX, _BX, etc are not defined in MicroSoft C 5.1. If there
are variables or functions which get and put register values, they aren't
documented.
Jon
--
Jon Brinkmann Astronomy Department
Internet: jvb7u@Virginia.EDU University of Virginia
UUCP: ...!uunet!virginia!jvb7u P.O. Box 3818
SPAN/HEPnet: 6654::jvb7u Charlottesville, VA 22903-0818moore@dtg.nsc.com (Joseph Moore) (01/31/91)
>In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes: >Is it possible in MSC 5.1 to gain access to the registers directly. >Turbo C has the _AX,_BX... pseudo-variables for them >is this possible in MSC and if so HOW??? > Yes, it's possible, but as far as I know only for interrupt calls, using the dos.h library structures REGS and SREGS. See the documentation in the run-time library reference under int86 and int86x (pp 365-369), or send me email for more info. Joe Moore
jvp@genrad.UUCP (Jim V. Potter) (01/31/91)
In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes: >Is it possible in MSC 5.1 to gain access to the registers directly. >Turbo C has the _AX,_BX... pseudo-variables for them >is this possible in MSC and if so HOW??? I suggest that you look at the union REGS defined in dos.h to see how to define registers that are passed to functions. The functions bdos(), int86(), int86x(), intdos(), and intdosx() are some functions that use the REGS union; see the Runtime Library manual for examples of calling these functions.
resnicks@netcom.UUCP (Steve Resnick) (02/01/91)
In article <676@dtg.nsc.com> moore@dtg.nsc.com (Joseph Moore) writes: >>In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes: >>Is it possible in MSC 5.1 to gain access to the registers directly. >>Turbo C has the _AX,_BX... pseudo-variables for them >>is this possible in MSC and if so HOW??? >> >Yes, it's possible, but as far as I know only for interrupt calls, >using the dos.h library structures REGS and SREGS. >See the documentation in the run-time library reference under int86 >and int86x (pp 365-369), or send me email for more info. > This is not the same thing, Joe. The Turbo C psuedo-variables are referenced as the register values at that point in the code. When you call int86, you are setting up a routine which loads the register variables from REGS and SREGS, calling your favorite interrupt and then reloading the variables back from the registers. This is, however, different than the psuedo-variables. In Turbo C, if you had a line of C which read: int x = _AX; The resulting 80x86 code would be mov [x],AX (x in this context is dependant on memory model) This cannot be done in MSC 5.1. It can't. Cheers! Steve -- ------------------------------------------------------------------------------- resnicks@netcom.com, apple!camphq!105!steve.resnick, IFNA: 1:143/105.0, USNail: 530 Lawrence Expressway, Suite 374 Sunnyvale, Ca 94086 - In real life: Steve Resnick. Flames, grammar and spelling errors >/dev/null 0x2b |~ 0x2b, THAT is the question. -------------------------------------------------------------------------------
bobf@intermec.UUCP (Bob Folline) (02/06/91)
>In article <91026.223149ACPS2924@Ryerson.Ca> ACPS2924@Ryerson.Ca writes: >>Is it possible in MSC 5.1 to gain access to the registers directly. >Nope. I believe MSC 6.0 supports this, but I am not sure.... Yes 6.0 will allow register access through either pointer or inline assembly. The manual gives a fair explanation of direct addressing.