bug#13342: [PARTIALLY SOLVED] bug#13342: Errors trying to build Guile 2.0.7

[Peter Teeson]

Hi Ludo:

MacOS 10.7.5 Intel Dual CPU quad cores 

Many thanks for your reply. A nice demo but, no disrespect, maybe not really the issue.

Looking at the generated code from each compiler was going to be my next step after

taking a look at the stack and regs to see what got passed/pushed/popped in the call to test_sum.

Which is why I posted about how can I debug/step through the interpreter. 

I still don't understand how to do that even though I read through the manual.

My experiment in building guile with both compilers indicate they both produce the same error.

bad return from _expression_ `(f-sum -1 2000 -30000 40000000000)': expected 39999971999; got 39999972255

I am still of the opinion that it's an interpreter issue and not a compiler one. 

I ask for help in confirming my understanding of this scheme code from the file 

/test-suite/standalone/test-ffi

;;

;; Multiple int args of differing types

;;

(define f-sum

  (pointer->procedure int64 (dynamic-func "test_ffi_sum" lib)

                      (list int8 int16 int32 int64)))

(test (f-sum -1 2000 -30000 40000000000)  ;; This calls the c function f-sum

      (+ -1 2000 -30000 40000000000))      ;;  This executes the scheme interpreter to do the sum

Is my understanding correct??????

If so please explain to me how the interpreter knows that the -1 in this _expression_ is an int8?

My suspicion is that it thinks it's an int16 and that's why we see the difference!!

I don't know how to pass an int8 of -1 to the interpreter in REPL mode.

Otherwise I'd try that.

============= from Terminal REPL session =============

Gandalf:guile-2.0.7 pteeson$ guile

GNU Guile 2.0.7

<snipped comments>

scheme@(guile-user)> (+ -1 2000 -30000 40000000000)

$1 = 39999971999

scheme@(guile-user)> ,q

which matches the fail message value.

bad return from _expression_ `(f-sum -1 2000 -30000 40000000000)': expected 39999971999; got 39999972255

================= from http://pubs.opengroup.org/onlinepubs/009695399/basedefs/stdint.h.html =========== 

Limits of exact-width integer types

Minimum values of exact-width signed integer types:

{INTN_MIN}

Exactly -(2 ^N-1)

Maximum values of exact-width signed integer types:

{INTN_MAX}

Exactly 2^N-1 -1

==========================================