|
DataMuseum.dkPresents historical artifacts from the history of: Commodore CBM-900 |
This is an automatic "excavation" of a thematic subset of
See our Wiki for more about Commodore CBM-900 Excavated with: AutoArchaeologist - Free & Open Source Software. |
top - download
Length: 23814 (0x5d06)
Types: TextFile
Notes: UNIX file
Names: »small2.s«
└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
└─⟦2d53db1df⟧ UNIX V7 Filesystem
└─ ⟦this⟧ »hr/src/smgr/small2.s«
#define srcptr rr6 #define srclow r7 #define srchi rh6 #define dstptr rr4 #define dstlow r5 #define dsthi rh4 #define fpline r1 #define lines r11 #define mask r10 #define dst2 rr12 #define dst2h r12 #define dst2l r13 .prvi .globl smt7, smt8, smt9, smt10, smt11, smt12, smt13, smt14, smt15 .globl smb7, smb8, smb9, smb10, smb11, smb12, smb13, smb14, smb15 .globl snb12 // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = src | dst // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt7: // src | dst // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION xor r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt7 // while more lines, repeat jp Small_ret smb7: // src | dst // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION xor r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb7 // while more lines, repeat jp Small_ret // // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = (~src) | (~dst) // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt8: // (~src) & (~dst) // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION com r3 com r9 // (~src) & ( ~dst) and r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment the src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt8 // while more lines, repeat jp Small_ret smb8: // (~src) & (~dst) // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION com r3 com r9 // (~src) & ( ~dst) and r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment the src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb8 // while more lines, repeat jp Small_ret // // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = (~src) ^ dst // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt9: // (~src) ^ dst // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION (~src) XOR dst com r3 xor r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt9 // while more lines, repeat jp Small_ret smb9: // (~src) ^ dst // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION (~src) XOR dst com r3 xor r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb9 // while more lines, repeat jp Small_ret // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = ~dst... pattern doesn't matter // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt10: // ~dst... pattern doesn't matter // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 // The operation (~dst) com r3 and r3, mask sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 sub r0, r0 add dstlow, BLT_dinc_ // increment dst ^ adcb dsthi, rh0 // check for segment overflow djnz lines, smt10 // while more lines, repeat jp Small_ret smb10: // ~dst... pattern doesn't matter // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 // The operation (~dst) com r3 and r3, mask sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 sub r0, r0 sub dstlow, BLT_dinc_ // increment dst ^ sbcb dsthi, rh0 // check for segment overflow djnz lines, smb10 // while more lines, repeat jp Small_ret // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = src | (~dst) // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt11: // src | (~dst) // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION src | (~dst) com r3 or r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment the src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt11 // while more lines, repeat jp Small_ret smb11: // src | (~dst) // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION src | (~dst) com r3 or r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment the src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb11 // while more lines, repeat jp Small_ret // // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = ~src // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ snb12: // ~src // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " ldl rr8, @srcptr // load thirty two bits of source ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION com r9 and r9, mask ld r3, r9 // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment the src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow djnz lines, snb12 // while more lines, repeat jp Small_ret smt12: // ~src // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION com r9 and r9, mask ld r3, r9 // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment the src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt12 // while more lines, repeat jp Small_ret smb12: // ~src // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION com r9 and r9, mask ld r3, r9 // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment the src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb12 // while more lines, repeat jp Small_ret // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = (~src) | dst // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt13: // (~src) | dst // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION (~src) | dst com r9 or r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment the src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt13 // while more lines, repeat jp Small_ret smb13: // (~src) | dst // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION (~src) | dst com r9 or r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment the src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb13 // while more lines, repeat jp Small_ret // // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = (~src) | (~dst) // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt14: // (~src) | (~dst) // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION (~src) | (~dst) com r3 com r9 or r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 add srclow, BLT_sinc_ // increment the src ^ adcb srchi, rh0 // check for segment overflow add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt14 // while more lines, repeat jp Small_ret smb14: // (~src) | (~dst) // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now perform the operation ... the dst word is still safe in rr2 ld r0, ds_ neg r0 // must be negative for right movement sdll rr2, r0 // the bits to change are in least sig bits // of r3 ldl rr8, @srcptr // load thirty two bits of source and r8, spat_(fpline)// src = src & pattern and r9, spat_(fpline)// src = src & pattern ld r0, ss_ neg r0 // must be negative for right movement sdll rr8, r0 // the bits to use for the change are now in // the least sig bits of r5 // THE OPERATION (~src) | (~dst) com r3 com r9 or r3, r9 and r3, mask // Shift the answer back over to line up with the hole and add it in sub r2, r2 ld r0, ds_ sdll rr2, r0 addl rr2, dst2 ldl @dstptr, rr2 // store it back in sub r0, r0 sub srclow, BLT_sinc_ // increment the src ^ sbcb srchi, rh0 // check for segment overflow sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb14 // while more lines, repeat jp Small_ret // // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // OP = true... all ones // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ smt15: // true...all 1's // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now add the full FFFF mask in sub r2, r2 ld r3, mask ld r0, ds_ sdll rr2, r0 and r2, spat_(fpline)// and in the pattern and r3, spat_(fpline)// again addl dst2, rr2 ldl @dstptr, dst2 sub r0, r0 add dstlow, BLT_dinc_ // increment the dst ^ adcb dsthi, rh0 // check for segment overflow inc fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smt15 // while more lines, repeat jp Small_ret smb15: // true...all 1's // first create the dst word with a hole in it for the new stuff ldl dst2, mask2_ // mask with hole in it ldl rr2, @dstptr // dst word and dst2h, r2 // 'and' them together and dst2l, r3 // " " " // now add the full FFFF mask in sub r2, r2 ld r3, mask ld r0, ds_ sdll rr2, r0 and r2, spat_(fpline) and r3, spat_(fpline)// again addl dst2, rr2 ldl @dstptr, dst2 sub r0, r0 sub dstlow, BLT_dinc_ // increment the dst ^ sbcb dsthi, rh0 // check for segment overflow dec fpline, $2 // increment pattern index and fpline, $31 // with wrap around at 16th line djnz lines, smb15 // while more lines, repeat jp Small_ret