--- /dev/null
+dnl Alpha mpn_divrem_2 -- Divide an mpn number by a normalized 2-limb number.
+
+dnl Copyright 2007, 2008 Free Software Foundation, Inc.
+
+dnl This file is part of the GNU MP Library.
+
+dnl The GNU MP Library is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU Lesser General Public License as published
+dnl by the Free Software Foundation; either version 3 of the License, or (at
+dnl your option) any later version.
+
+dnl The GNU MP Library is distributed in the hope that it will be useful, but
+dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+dnl License for more details.
+
+dnl You should have received a copy of the GNU Lesser General Public License
+dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
+
+include(`../config.m4')
+
+C norm frac
+C ev4
+C ev5 70 70
+C ev6 29 29
+
+C TODO
+C * Perhaps inline mpn_invert_limb, that would allow us to not save/restore
+C any registers (thus save ~10 cycles per call).
+C * Use negated d1 and/or d0 to speed carry propagation. Might save a cycle
+C or two.
+C * Check cluster delays (for ev6). We very likely could save some cycles.
+C * Use branch-free code for computing di.
+C * CAVEAT: We rely on r19 not being clobbered by mpn_invert_limb call.
+
+C INPUT PARAMETERS
+define(`qp', `r16')
+define(`fn', `r17')
+define(`up_param', `r18')
+define(`un_param', `r19')
+define(`dp', `r20')
+
+ASM_START()
+PROLOGUE(mpn_divrem_2)
+ ldgp r29, 0(r27)
+ lda r30, -80(r30)
+ stq r26, 0(r30)
+ stq r9, 8(r30)
+ stq r10, 16(r30)
+ stq r11, 24(r30)
+ stq r12, 32(r30)
+ stq r13, 40(r30)
+C stq r14, 48(r30)
+ stq r15, 56(r30)
+ .prologue 1
+ stq r16, 64(r30)
+ bis r31, r17, r15
+ s8addq r19, r18, r13
+ lda r13, -24(r13)
+ ldq r12, 8(r20)
+ ldq r10, 0(r20)
+ ldq r11, 16(r13)
+ ldq r9, 8(r13)
+
+ bis r31, r31, r3 C most_significant_q_limb = 0
+ cmpult r11, r12, r1
+ bne r1, L(L8)
+ cmpule r11, r12, r1
+ cmpult r9, r10, r2
+ and r1, r2, r1
+ bne r1, L(L8)
+ subq r11, r12, r11
+ subq r11, r2, r11
+ subq r9, r10, r9
+ lda r3, 1(r31) C most_significant_q_limb = 1
+L(L8): stq r3, 72(r30)
+
+ addq r15, r19, r19
+ lda r19, -3(r19)
+ blt r19, L(L10)
+ bis r31, r12, r16
+ jsr r26, mpn_invert_limb
+ ldgp r29, 0(r26)
+ mulq r0, r12, r4 C t0 = LO(di * d1)
+ umulh r0, r10, r2 C s1 = HI(di * d0)
+ addq r4, r10, r4 C t0 += d0
+ cmpule r10, r4, r7 C (t0 < d0)
+ addq r4, r2, r4 C t0 += s1
+ cmpult r4, r2, r1
+ subq r1, r7, r7 C t1 (-1, 0, or 1)
+ blt r7, L(L42)
+L(L22):
+ lda r0, -1(r0) C di--
+ cmpult r4, r12, r1 C cy for: t0 -= d1 (below)
+ subq r7, r1, r7 C t1 -= cy
+ subq r4, r12, r4 C t0 -= d1
+ bge r7, L(L22)
+L(L42):
+ ldq r16, 64(r30)
+ s8addq r19, r16, r16
+ ALIGN(16)
+L(loop):
+ mulq r11, r0, r5 C q0 (early)
+ umulh r11, r0, r6 C q (early)
+ addq r5, r9, r8 C q0 += n1
+ addq r6, r11, r6 C q += n2
+ cmpult r8, r5, r1 C cy for: q0 += n1
+ addq r6, r1, r6 C q += cy
+ unop
+ mulq r12, r6, r1 C LO(d1 * q)
+ umulh r10, r6, r7 C t1 = HI(d0 * q)
+ subq r9, r1, r9 C n1 -= LO(d1 * q)
+ mulq r10, r6, r4 C t0 = LO(d0 * q)
+ unop
+ cmple r15, r19, r5 C condition and n0...
+ beq r5, L(L31)
+ ldq r5, 0(r13)
+ lda r13, -8(r13)
+L(L31): subq r9, r12, r9 C n1 -= d1
+ cmpult r5, r10, r1 C
+ subq r9, r1, r9 C
+ subq r5, r10, r5 C n0 -= d0
+ subq r9, r7, r9 C n1 -= t0
+ cmpult r5, r4, r1 C
+ subq r9, r1, r2 C
+ subq r5, r4, r5 C n0 -= t1
+ cmpult r2, r8, r1 C (n1 < q0)
+ addq r6, r1, r6 C q += cond
+ lda r1, -1(r1) C -(n1 >= q0)
+ and r1, r10, r4 C
+ addq r5, r4, r9 C n0 += mask & d0
+ and r1, r12, r1 C
+ cmpult r9, r5, r11 C cy for: n0 += mask & d0
+ addq r2, r1, r1 C n1 += mask & d1
+ addq r1, r11, r11 C n1 += cy
+ cmpult r11, r12, r1 C
+ beq r1, L(fix) C
+L(bck): stq r6, 0(r16)
+ lda r16, -8(r16)
+ lda r19, -1(r19)
+ bge r19, L(loop)
+
+L(L10): stq r9, 8(r13)
+ stq r11, 16(r13)
+ ldq r0, 72(r30)
+ ldq r26, 0(r30)
+ ldq r9, 8(r30)
+ ldq r10, 16(r30)
+ ldq r11, 24(r30)
+ ldq r12, 32(r30)
+ ldq r13, 40(r30)
+C ldq r14, 48(r30)
+ ldq r15, 56(r30)
+ lda r30, 80(r30)
+ ret r31, (r26), 1
+
+L(fix): cmpule r11, r12, r1
+ cmpult r9, r10, r2
+ and r1, r2, r1
+ bne r1, L(bck)
+ subq r11, r12, r11
+ subq r11, r2, r11
+ subq r9, r10, r9
+ lda r6, 1(r6)
+ br L(bck)
+EPILOGUE()
+ASM_END()
projects / msp430-gcc.git / blobdiff