added peepholes 182.d (return 0.0), 256 (range check), 257 (do while), 258.a-f ...

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3366 4a8a32a2-be11-0410-ad9d-d568d2c75423

diff --git a/src/mcs51/peeph.def b/src/mcs51/peeph.def
index 98a65b9e58f0ef4619b82a2eed0fc545f054a485..6225543dfcc0e051627705fc3ea2fe8b15b37e34 100644 (file)
--- a/src/mcs51/peeph.def
+++ b/src/mcs51/peeph.def
@@ -1120,6 +1120,17 @@ replace {
        mov     dptr,#(((%2)<<8) + %1)
 }
 
+// applies to return 0.0; in f.e. sincosf.c
+replace {
+       mov     dpl,#%1
+       clr     a
+       mov     dph,a
+} by {
+       ;       Peephole 182.d  used 16 bit load of dptr
+       mov     dptr,#(%1&0x00ff)
+       clr     a
+}
+
 replace {
        anl     %1,#%2
        anl     %1,#%3
@@ -3095,14 +3106,14 @@ replace {
        jnz     %1
 %1:
 } by {
-       ;       Peephole 249a    jump optimization
+       ;       Peephole 249.a   jump optimization
 } if labelRefCount %1 1
 
 replace {
        jz      %1
 %1:
 } by {
-       ;       Peephole 249b    jump optimization
+       ;       Peephole 249.b   jump optimization
 } if labelRefCount %1 1
 
 
@@ -3204,6 +3215,7 @@ replace {
        ret
 }
 
+
 // applies to f.e. funptrs.c
 // saves one byte if %1 is a register or @register
 replace {
@@ -3238,3 +3250,154 @@ replace {
        mov     dptr,%5
        jmp     @a+dptr
 }
+
+// applies to f.e. jump tables and scott-bool1.c.
+// similar peepholes can be constructed for other instructions 
+// after which a flag or a register is known (like: djnz, cjne, jnc)
+replace {
+       jc      %1
+%2:
+       clr     c
+} by {
+       ;       Peephole 256.a  removed redundant clr c
+       jc      %1
+%2:
+} if labelRefCount %2 0
+
+// applies to f.e. logf.c
+replace {
+       jnz     %1
+%2:
+       clr     a
+} by {
+       ;       Peephole 256.b  removed redundant clr a
+       jnz     %1
+%2:
+} if labelRefCount %2 0
+
+
+// unsigned char i=8; do{ } while(--i != 0);
+// this currently only applies if i is kept in a register
+replace {
+       dec     %1
+       cjne    %1,#0x00,%2
+} by {
+       ;       Peephole 257    optimized decrement with compare
+       djnz    %1,%2
+} if notVolatile %1
+
+
+// in_byte<<=1; if(in_bit) in_byte|=1;
+// helps f.e. reading data on a 3-wire (SPI) bus
+replace {
+       mov     a,%1
+       add     a,%1
+       mov     %1,a
+       jnb     %2,%3
+%4:
+       orl     %1,#0x01
+%3:
+} by {
+       ;       Peephole 258.a  optimized bitbanging
+       mov     a,%1
+       mov     c,%2
+       addc    a,%1
+       mov     %1,a
+%4:
+%3:       
+} if notVolatile %1
+
+// in_byte<<=1; if(in_bit) in_byte|=1;
+replace {
+       mov     a,r%1
+       add     a,r%1
+       mov     r%1,a
+       jnb     %2,%3
+%4:
+       orl     ar%1,#0x01
+%3:
+} by {
+       ;       Peephole 258.b  optimized bitbanging
+       mov     a,r%1
+       mov     c,%2
+       addc    a,r%1
+       mov     r%1,a
+%4:
+%3:
+}
+
+// in_byte>>=1; if(in_bit) in_byte|=0x80;
+replace {
+       mov     a,%1
+       clr     c
+       rrc     a
+       mov     %1,a
+       jnb     %2,%3
+%4:
+       orl     %1,#0x80
+%3:
+} by {
+       ;       Peephole 258.c  optimized bitbanging
+       mov     a,%1
+       mov     c,%2
+       rrc     a
+       mov     %1,a
+%4:
+%3:
+} if notVolatile %1
+
+// in_byte>>=1; if(in_bit) in_byte|=0x80;
+replace {
+       mov     a,r%1
+       clr     c
+       rrc     a
+       mov     r%1,a
+       jnb     %2,%3
+%4:
+       orl     ar%1,#0x80
+%3:
+} by {
+       ;       Peephole 258.d  optimized bitbanging
+       mov     a,r%1
+       mov     c,%2
+       rrc     a
+       mov     r%1,a
+%4:
+%3:
+}
+
+// out_bit=out_byte&0x80; out_byte<<=1;
+// helps f.e. writing data on a 3-wire (SPI) bus
+replace {
+       mov     a,%1
+       mov     c,acc.7
+       mov     %2,c
+       mov     a,%1
+       add     a,%1
+       mov     %1,a
+} by {
+       ;       Peephole 258.e  optimized bitbanging
+       mov     a,%1
+       add     a,%1
+       mov     %2,c
+       mov     %1,a
+} if notVolatile %1 
+
+// out_bit=out_byte&0x01; out_byte>>=1;
+replace {
+       mov     a,%1
+       mov     c,acc.0
+       mov     %2,c
+       mov     a,%1
+       clr     c
+       rrc     a
+       mov     %1,a
+} by {
+       ;       Peephole 258.f  optimized bitbanging
+       mov     a,%1
+       clr     c
+       rrc     a
+       mov     %2,c
+       mov     %1,a
+} if notVolatile %1
+