Mercurial > hg > Members > kono > nitros9-code
view lib/alib/mult16x8.a @ 2546:f0977fc3f2d6
Added code for Gary's CoCo3FPGA interface
author | boisy |
---|---|
date | Sat, 12 Jun 2010 11:59:39 +0000 |
parents | 7d70b7e1cb21 |
children | aaba193af04f |
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*********************************** * 16 x 8 Multiply (24 bit result) * OTHER MODULES NEEDED: none * ENTRY: A = multiplier * X = multiplicand * EXIT: A = product byte 1 * X = product bytes 2 & 3 nam 16x8 bit Multiply ttl Assembler Library Module psect MULT168,0,0,0,0,0 MULT168: PSHS A,X save numbers LEAS -3,S room for product LDB 5,S get lsb of multiplicand MUL STD 1,S save partial product LDD 3,S get mupltiplier & msb of multp. MUL ADDB 1,S add lsb to msb ADCA #0 add carry STD 0,S save sum of partial products LDX 1,S get 2 lsb's LEAS 6,S clean stack RTS endsect