Mercurial > hg > Members > kono > nitros9-code
view lib/alib/mult16x16.a @ 2772:0a3f4d8ea6d5
Found ENDC in wrong location in dwread.asm and dwwrite.asm. Corrected.
Moved the native 6309 code in dwread.asm and dwwrite.asm into the H6309 labeled area and changed IFEQ H6309 to IFNE H6309. Also moved the 57600bps 6809 code to the default location. This change had been done in the old dwread.asm and dwwrite.asm files to make it easier to follow. Though these two files were overwritten from the HDBDOS project dwread.asm and dwwrite.asm files. So this conversion needed to be done again so it made the source easier to follow.
| author | drencor-xeen |
|---|---|
| date | Wed, 23 Jan 2013 12:36:55 -0600 |
| parents | 7d70b7e1cb21 |
| children | aaba193af04f |
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************************************ * 16 x 16 Multiply * ENTRY: D = multiplier * X = multiplicand * EXIT: Y = product 2 msbs * U = " 2 lsbs * D & X preserved nam 16x16 bit Multiply ttl Assembler Library Module psect MULT16,0,0,0,0,0 MULT16: PSHS D,X,Y,U save #s and make stack room CLR 4,S reset overflow flag LDA 3,S get byte MUL STD 6,S save B x Xl LDD 1,S MUL B x Xh ADDB 6,S ADCA #0 STD 5,S add 1st 2 mult. LDB 0,S LDA 3,S MUL A x Xl ADDD 5,S STD 5,S add result to previous BCC no.ov branch if no overflow INC 4,S set overflow flag no.ov LDA 0,S LDB 2,S MUL A x Xh ADDD 4,S STD 4,S PULS D,X,Y,U,PC return endsect