gcc bug? (was bug in gen5200/tod/pcf8563.c)

Wolfram Wadepohl Wolfram.Wadepohl at ek-automation.com
Tue May 15 05:50:16 UTC 2007

Ingolf Steinbach schrieb:

> I don't know PPC assembly either. But maybe the reason for your
> problem becomes obvious if you compare the assembler code resulting
> from the macro version with the assembler code resulting from the
> inline function version of From_BCD(). Could you post both of them?


here is the inline version (output from list windows in TRACE32):
             |    v1 = info[PCF8563_DAY_ADR-PCF8563_SECOND_ADR] & 
          175|    time->day = From_BCD(v1);
  SF:000C7D88|5520E13E            srwi      r0,r9,0x4      ; r0,r9,CS0STR
  SF:000C7D8C|1C00000A            mulli     r0,r0,0x0A     ; r0,r0,10
  SF:000C7D90|5529073E            clrlwi    r9,r9,0x1C     ; r9,r9,GP_18
  SF:000C7D94|7C004A14            add       r0,r0,r9
  SF:000C7D98|901E0008            stw       r0,0x8(r30)    ; r0,CS0STP(r30)
  SF:000C7D9C|8921000A            lbz       r9,0x0A(r1)    ; r9,10(r1)
  SF:000C7DA0|552906BE            clrlwi    r9,r9,0x1A     ; r9,r9,26
             |    v1 = info[PCF8563_HOUR_ADR-PCF8563_SECOND_ADR] & 
          178|    time->hour = From_BCD(v1);
  SF:000C7DA4|5520E13E            srwi      r0,r9,0x4      ; r0,r9,CS0STR
  SF:000C7DA8|1C00000A            mulli     r0,r0,0x0A     ; r0,r0,10
  SF:000C7DAC|5529073E            clrlwi    r9,r9,0x1C     ; r9,r9,GP_18
  SF:000C7DB0|7C004A14            add       r0,r0,r9
  SF:000C7DB4|901E000C            stw       r0,0x0C(r30)   ; r0,CS1STR(r30)
  SF:000C7DB8|89210009            lbz       r9,0x9(r1)     ; r9,9(r1)
  SF:000C7DBC|5529067E            clrlwi    r9,r9,0x19     ; r9,r9,25
             |    v1 = info[PCF8563_MINUTE_ADR-PCF8563_SECOND_ADR] & 
          181|    time->minute = From_BCD(v1);
  SF:000C7DC0|5520E13E            srwi      r0,r9,0x4      ; r0,r9,CS0STR
  SF:000C7DC4|1C00000A            mulli     r0,r0,0x0A     ; r0,r0,10
  SF:000C7DC8|5529073E            clrlwi    r9,r9,0x1C     ; r9,r9,GP_18
  SF:000C7DCC|7C004A14            add       r0,r0,r9
  SF:000C7DD0|901E0010            stw       r0,0x10(r30)   ; r0,CS1STP(r30)
  SF:000C7DD4|89210008            lbz       r9,0x8(r1)     ; r9,info(r1)

and here the macro version:
          165|    v1 = info[PCF8563_DAY_ADR-PCF8563_SECOND_ADR] & 
  SF:000C6840|8961000B            lbz       r11,0x0B(r1)   ; r11,11(r1)
          166|    time->day = From_BCD(v1);
  SF:000C6844|5569E7BE            extrwi    r9,r11,0x2,0x1A; 
  SF:000C6848|1D29000A            mulli     r9,r9,0x0A     ; r9,r9,10
  SF:000C684C|556B073E            clrlwi    r11,r11,0x1C   ; r11,r11,GP_18
  SF:000C6850|7D295A14            add       r9,r9,r11
  SF:000C6854|913E0008            stw       r9,0x8(r30)    ; r9,CS0STP(r30)
          168|    v1 = info[PCF8563_HOUR_ADR-PCF8563_SECOND_ADR] & 
  SF:000C6858|8801000A            lbz       r0,0x0A(r1)    ; r0,10(r1)
          169|    time->hour = From_BCD(v1);
_SF:000C685C|5400077A            rlwinm    r0,r0,0x0,0x1D,0x1D;_r0,r0,0,29,29
  SF:000C6860|901E000C            stw       r0,0x0C(r30)   ; r0,CS1STR(r30)
          171|    v1 = info[PCF8563_MINUTE_ADR-PCF8563_SECOND_ADR] & 
  SF:000C6864|89210009            lbz       r9,0x9(r1)     ; r9,9(r1)
          172|    time->minute = From_BCD(v1);
  SF:000C6868|5520E77E            extrwi    r0,r9,0x3,0x19 ; r0,r9,3,25
  SF:000C686C|1C00000A            mulli     r0,r0,0x0A     ; r0,r0,10
  SF:000C6870|5529073E            clrlwi    r9,r9,0x1C     ; r9,r9,GP_18
  SF:000C6874|7C004A14            add       r0,r0,r9
  SF:000C6878|901E0010            stw       r0,0x10(r30)   ; r0,CS1STP(r30)

it is obvious that the code generated for line 169 of the macro version 
does not do the same computation as the code of the inlined version (line 
178). differnces in line numbering because of the function definitions for 
inline functions in source file.

my question: is this a misbehaviour of the gcc? i'm using cygwin tools
powerpc-rtems4.7-gcc (GCC) 4.0.1
(RTEMS gcc-4.0.1-20050810/newlib-1.13.0-20050810-4)

Schöne Grüße aus Reutlingen

Wolfram Wadepohl
Forschung & Entwicklung

Indumat GmbH & Co. KG
Siemensstraße 3
72766 Reutlingen

Tel.  +49 7121 514-289
Fax   +49 7121 514-299
eMail Wolfram.Wadepohl at ek-automation.com
       W.Wadepohl at ieee.org
WWW   http://www.ek-automation.com

Diese Nachricht ist keine geschäftliche Mitteilung i. S. des EHUG.

Bitte senden Sie mir keine Word- oder PowerPoint- (tm Microsoft) Anhänge.
Senden Sie mir einfachen Text, HTML oder PDF.
Siehe http://www.gnu.org/philosophy/no-word-attachments.de.html

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 3210 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.rtems.org/pipermail/users/attachments/20070515/f5b7da4c/attachment-0001.bin>

More information about the users mailing list