diff options
Diffstat (limited to 'ports/sysdeps/m68k/m680x0/rshift.S')
| -rw-r--r-- | ports/sysdeps/m68k/m680x0/rshift.S | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/ports/sysdeps/m68k/m680x0/rshift.S b/ports/sysdeps/m68k/m680x0/rshift.S new file mode 100644 index 0000000000..f5f2f3d69a --- /dev/null +++ b/ports/sysdeps/m68k/m680x0/rshift.S @@ -0,0 +1,167 @@ +/* mc68020 __mpn_rshift -- Shift right a low-level natural-number integer. + +Copyright (C) 1996, 1998, 2012 Free Software Foundation, Inc. + +This file is part of the GNU MP Library. + +The GNU MP Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 of the License, or (at your +option) any later version. + +The GNU MP Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the GNU MP Library. If not, see <http://www.gnu.org/licenses/>. */ + +/* + INPUT PARAMETERS + res_ptr (sp + 4) + s_ptr (sp + 8) + s_size (sp + 16) + cnt (sp + 12) +*/ + +#include "sysdep.h" +#include "asm-syntax.h" + +#define res_ptr a1 +#define s_ptr a0 +#define s_size d6 +#define cnt d4 + + TEXT +ENTRY(__mpn_rshift) +/* Save used registers on the stack. */ + moveml R(d2)-R(d6)/R(a2),MEM_PREDEC(sp) + cfi_adjust_cfa_offset (6*4) + cfi_rel_offset (R(d2), 0) + cfi_rel_offset (R(d3), 4) + cfi_rel_offset (R(d4), 8) + cfi_rel_offset (R(d5), 12) + cfi_rel_offset (R(d6), 16) + cfi_rel_offset (R(a2), 20) + +/* Copy the arguments to registers. */ + movel MEM_DISP(sp,28),R(res_ptr) + movel MEM_DISP(sp,32),R(s_ptr) + movel MEM_DISP(sp,36),R(s_size) + movel MEM_DISP(sp,40),R(cnt) + + moveql #1,R(d5) + cmpl R(d5),R(cnt) + bne L(Lnormal) + cmpl R(res_ptr),R(s_ptr) + bls L(Lspecial) /* jump if res_ptr >= s_ptr */ +#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020)) + lea MEM_INDX1(res_ptr,s_size,l,4),R(a2) +#else /* not mc68020 */ + movel R(s_size),R(d0) + asll #2,R(d0) + lea MEM_INDX(res_ptr,d0,l),R(a2) +#endif + cmpl R(s_ptr),R(a2) + bls L(Lspecial) /* jump if s_ptr >= res_ptr + s_size */ + +L(Lnormal:) + moveql #32,R(d5) + subl R(cnt),R(d5) + movel MEM_POSTINC(s_ptr),R(d2) + movel R(d2),R(d0) + lsll R(d5),R(d0) /* compute carry limb */ + + lsrl R(cnt),R(d2) + movel R(d2),R(d1) + subql #1,R(s_size) + beq L(Lend) + lsrl #1,R(s_size) + bcs L(L1) + subql #1,R(s_size) + +L(Loop:) + movel MEM_POSTINC(s_ptr),R(d2) + movel R(d2),R(d3) + lsll R(d5),R(d3) + orl R(d3),R(d1) + movel R(d1),MEM_POSTINC(res_ptr) + lsrl R(cnt),R(d2) +L(L1:) + movel MEM_POSTINC(s_ptr),R(d1) + movel R(d1),R(d3) + lsll R(d5),R(d3) + orl R(d3),R(d2) + movel R(d2),MEM_POSTINC(res_ptr) + lsrl R(cnt),R(d1) + + dbf R(s_size),L(Loop) + subl #0x10000,R(s_size) + bcc L(Loop) + +L(Lend:) + movel R(d1),MEM(res_ptr) /* store most significant limb */ + +/* Restore used registers from stack frame. */ + moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2) + cfi_remember_state + cfi_adjust_cfa_offset (-6*4) + cfi_restore (R(d2)) + cfi_restore (R(d3)) + cfi_restore (R(d4)) + cfi_restore (R(d5)) + cfi_restore (R(d6)) + cfi_restore (R(a2)) + rts + +/* We loop from most significant end of the arrays, which is only + permissible if the source and destination don't overlap, since the + function is documented to work for overlapping source and destination. */ + + cfi_restore_state +L(Lspecial:) +#if (defined (__mc68020__) || defined (__NeXT__) || defined(mc68020)) + lea MEM_INDX1(s_ptr,s_size,l,4),R(s_ptr) + lea MEM_INDX1(res_ptr,s_size,l,4),R(res_ptr) +#else /* not mc68000 */ + movel R(s_size),R(d0) + asll #2,R(d0) + addl R(s_size),R(s_ptr) + addl R(s_size),R(res_ptr) +#endif + + clrl R(d0) /* initialize carry */ + eorw #1,R(s_size) + lsrl #1,R(s_size) + bcc L(LL1) + subql #1,R(s_size) + +L(LLoop:) + movel MEM_PREDEC(s_ptr),R(d2) + roxrl #1,R(d2) + movel R(d2),MEM_PREDEC(res_ptr) +L(LL1:) + movel MEM_PREDEC(s_ptr),R(d2) + roxrl #1,R(d2) + movel R(d2),MEM_PREDEC(res_ptr) + + dbf R(s_size),L(LLoop) + roxrl #1,R(d0) /* save cy in msb */ + subl #0x10000,R(s_size) + bcs L(LLend) + addl R(d0),R(d0) /* restore cy */ + bra L(LLoop) + +L(LLend:) +/* Restore used registers from stack frame. */ + moveml MEM_POSTINC(sp),R(d2)-R(d6)/R(a2) + cfi_adjust_cfa_offset (-6*4) + cfi_restore (R(d2)) + cfi_restore (R(d3)) + cfi_restore (R(d4)) + cfi_restore (R(d5)) + cfi_restore (R(d6)) + cfi_restore (R(a2)) + rts +END(__mpn_rshift) |