johnl@ima.istc.sri.com (08/19/87)
I need to find out what optimizing C compilers exist for the 68000. I
have found, based on personal experience, that while Green Hills makes
an awesome optimizing compiler, it gives up too much performance by
using 32 bit ints, and it would be too painful to change the existing
code I need to compile.
Does anyone out there know of a C compiler for the 68k that uses 16
bit ints and is of comparable quality to the Green Hills compiler?
Thanks in advance,
-Zigurd
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mail accidentally sent back to compilers. Meta-mail to ima!compilers-requestjohnl@ima.UUCP (08/20/87)
In article <672@ima.ISC.COM> you write: >I need to find out what optimizing C compilers exist for the 68000. I >have found, based on personal experience, that while Green Hills makes >an awesome optimizing compiler, it gives up too much performance by >using 32 bit ints, and it would be too painful to change the existing >code I need to compile. We use the Green Hills compiler here. I don't see how Green Hills burns performance by using 32-bit ints. Especially since they seem to benchmark faster than any other compiler! :-) In general it seems to be a win, as the compiler places variables in registers whenever possible, and the 68000's registers are 32-bit. My first take was that 16-bit int's might be more efficient, but there is some added overhead for clearing out the upper part of the register. Can you justify your statement? -- Preston L. Bannister USENET : ucbvax!trwrb!felix!preston BIX : plb CompuServe : 71350,3505 GEnie : p.bannister -- Send compilers articles to ima!compilers or, in a pinch, to Levine@YALE.ARPA Plausible paths are { ihnp4 | decvax | cbosgd | harvard | yale | cca}!ima Please send responses to the originator of the message -- I cannot forward mail accidentally sent back to compilers. Meta-mail to ima!compilers-request
zrm@EDDIE.MIT.EDU (Zigurd R. Mednieks) (08/21/87)
In article <683@ima.ISC.COM> decvax!ucbvax!hplabs!felix!preston (Preston Bannister) writes: >We use the Green Hills compiler here. I don't see how Green Hills >burns performance by using 32-bit ints. Especially since they seem to >benchmark faster than any other compiler! :-) In general it seems to The Macintosh Programmer's Workbench compiler is the Green Hills compiler and it bechmarks about 10% slower than the fairly simple Aztec C and LightspeedC compilers. I've read tons of GreenHills generated code and I know the potential is there, considering how good the code is, but the fact remains that on 68000s, using 32 bit ints does cost you at least 10% in performance. Let me emphasize that the 68000, not the 68020, is the target for which those benchmark figures hold true. I would expect the Green Hills compiler to do much better on the 68020. By the way, there is no need to clear the high word of a register when using the default 16-bit word length on 68000 instructions. I would rather see a compiler's cleverness applied to taking good advantage of 16 bit ints than frittered away on compensating for 32 bit ints. -Zigurd -- Send compilers articles to ima!compilers or, in a pinch, to Levine@YALE.ARPA Plausible paths are { ihnp4 | decvax | cbosgd | harvard | yale | cca}!ima Please send responses to the originator of the message -- I cannot forward mail accidentally sent back to compilers. Meta-mail to ima!compilers-request
johnl@ima.UUCP (08/23/87)
In article <672@ima.ISC.COM> you write: >I need to find out what optimizing C compilers exist for the 68000. I >have found, based on personal experience, that while Green Hills makes >an awesome optimizing compiler... I have cross-posted this to comp.sys.mac, where a discussion of the remarkably poor code-generation of Mac-targeted 68k C compilers is going on (in rn, use /stupid/b). Cross-fertilization seems in order... --dave -- David Collier-Brown. {mnetor|yetti|utgpu}!geac!daveb Geac Computers International Inc., | Computer Science loses its 350 Steelcase Road,Markham, Ontario, | memory (if not its mind) CANADA, L3R 1B3 (416) 475-0525 x3279 | every 6 months. -- Send compilers articles to ima!compilers or, in a pinch, to Levine@YALE.ARPA Plausible paths are { ihnp4 | decvax | cbosgd | harvard | yale | cca}!ima Please send responses to the originator of the message -- I cannot forward mail accidentally sent back to compilers. Meta-mail to ima!compilers-request