Linux/arch/riscv/lib/memmove.S

Version: ~ [ linux-6.12-rc7 ] ~ [ linux-6.11.7 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.60 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.116 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.171 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.229 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.285 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.323 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.12 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

Diff markup

1 /* SPDX-License-Identifier: GPL-2.0-only */ !! 1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* !! 2 /* memmove.S: Simple memmove implementation. 3 * Copyright (C) 2022 Michael T. Kloos <michael !! 3 * >> 4 * Copyright (C) 1997, 2004 David S. Miller (davem@redhat.com) >> 5 * Copyright (C) 1996, 1997, 1998, 1999 Jakub Jelinek (jj@ultra.linux.cz) 4 */ 6 */ 5 7 >> 8 #include <linux/export.h> 6 #include <linux/linkage.h> 9 #include <linux/linkage.h> 7 #include <asm/asm.h> << 8 10 9 SYM_FUNC_START(__memmove) !! 11 .text 10 /* !! 12 ENTRY(memmove) /* o0=dst o1=src o2=len */ 11 * Returns !! 13 brz,pn %o2, 99f 12 * a0 - dest !! 14 mov %o0, %g1 13 * !! 15 14 * Parameters !! 16 cmp %o0, %o1 15 * a0 - Inclusive first byte of dest !! 17 bleu,pt %xcc, 2f 16 * a1 - Inclusive first byte of src !! 18 add %o1, %o2, %g7 17 * a2 - Length of copy n !! 19 cmp %g7, %o0 18 * !! 20 bleu,pt %xcc, memcpy 19 * Because the return matches the para !! 21 add %o0, %o2, %o5 20 * we will not clobber or modify that !! 22 sub %g7, 1, %o1 21 * !! 23 22 * Note: This currently only works on !! 24 sub %o5, 1, %o0 23 * To port to big-endian, reverse the !! 25 1: ldub [%o1], %g7 24 * in the 2 misaligned fixup copy loop !! 26 subcc %o2, 1, %o2 25 */ !! 27 sub %o1, 1, %o1 26 !! 28 stb %g7, [%o0] 27 /* Return if nothing to do */ !! 29 bne,pt %icc, 1b 28 beq a0, a1, .Lreturn_from_memmove !! 30 sub %o0, 1, %o0 29 beqz a2, .Lreturn_from_memmove !! 31 99: 30 !! 32 retl 31 /* !! 33 mov %g1, %o0 32 * Register Uses !! 34 33 * Forward Copy: a1 - Index count !! 35 /* We can't just call memcpy for these memmove cases. On some 34 * Reverse Copy: a4 - Index count !! 36 * chips the memcpy uses cache initializing stores and when dst 35 * Forward Copy: t3 - Index count !! 37 * and src are close enough, those can clobber the source data 36 * Reverse Copy: t4 - Index count !! 38 * before we've loaded it in. 37 * Both Copy Modes: t5 - Inclusive f !! 39 */ 38 * Both Copy Modes: t6 - Non-Inclusi !! 40 2: or %o0, %o1, %g7 39 * Both Copy Modes: t0 - Link / Temp !! 41 or %o2, %g7, %g7 40 * Both Copy Modes: t1 - Temporary f !! 42 andcc %g7, 0x7, %g0 41 * Both Copy Modes: t2 - Temporary f !! 43 bne,pn %xcc, 4f 42 * Both Copy Modes: a5 - dest to src !! 44 nop 43 * Both Copy Modes: a6 - Shift ammou !! 45 44 * Both Copy Modes: a7 - Inverse Shi !! 46 3: ldx [%o1], %g7 45 * Both Copy Modes: a2 - Alternate b !! 47 add %o1, 8, %o1 46 */ !! 48 subcc %o2, 8, %o2 47 !! 49 add %o0, 8, %o0 48 /* !! 50 bne,pt %icc, 3b 49 * Solve for some register values now. !! 51 stx %g7, [%o0 - 0x8] 50 * Byte copy does not need t5 or t6. !! 52 ba,a,pt %xcc, 99b 51 */ !! 53 52 mv t3, a0 !! 54 4: ldub [%o1], %g7 53 add t4, a0, a2 !! 55 add %o1, 1, %o1 54 add a4, a1, a2 !! 56 subcc %o2, 1, %o2 55 !! 57 add %o0, 1, %o0 56 /* !! 58 bne,pt %icc, 4b 57 * Byte copy if copying less than (2 * !! 59 stb %g7, [%o0 - 0x1] 58 * cause problems with the bulk copy i !! 60 ba,a,pt %xcc, 99b 59 * small enough not to bother. !! 61 ENDPROC(memmove) 60 */ !! 62 EXPORT_SYMBOL(memmove) 61 andi t0, a2, -(2 * SZREG) << 62 beqz t0, .Lbyte_copy << 63 << 64 /* << 65 * Now solve for t5 and t6. << 66 */ << 67 andi t5, t3, -SZREG << 68 andi t6, t4, -SZREG << 69 /* << 70 * If dest(Register t3) rounded down t << 71 * aligned SZREG address, does not equ << 72 * to find the low-bound of SZREG alig << 73 * region. Note that this could overs << 74 * region if n is less than SZREG. Th << 75 * we always byte copy if n is less th << 76 * Otherwise, dest is already naturall << 77 */ << 78 beq t5, t3, 1f << 79 addi t5, t5, SZREG << 80 1: << 81 << 82 /* << 83 * If the dest and src are co-aligned << 84 * no need for the full rigmarole of a << 85 * Instead, do a simpler co-aligned co << 86 */ << 87 xor t0, a0, a1 << 88 andi t1, t0, (SZREG - 1) << 89 beqz t1, .Lcoaligned_copy << 90 /* Fall through to misaligned fixup co << 91 << 92 .Lmisaligned_fixup_copy: << 93 bltu a1, a0, .Lmisaligned_fixup_copy_r << 94 << 95 .Lmisaligned_fixup_copy_forward: << 96 jal t0, .Lbyte_copy_until_aligned_for << 97 << 98 andi a5, a1, (SZREG - 1) /* Find the a << 99 slli a6, a5, 3 /* Multiply by 8 to con << 100 sub a5, a1, t3 /* Find the difference << 101 andi a1, a1, -SZREG /* Align the src p << 102 addi a2, t6, SZREG /* The other breakp << 103 << 104 /* << 105 * Compute The Inverse Shift << 106 * a7 = XLEN - a6 = XLEN + -a6 << 107 * 2s complement negation to find the << 108 * Add that to XLEN. XLEN = SZREG * 8 << 109 */ << 110 not a7, a6 << 111 addi a7, a7, (SZREG * 8 + 1) << 112 << 113 /* << 114 * Fix Misalignment Copy Loop - Forwar << 115 * load_val0 = load_ptr[0]; << 116 * do { << 117 * load_val1 = load_ptr[1]; << 118 * store_ptr += 2; << 119 * store_ptr[0 - 2] = (load_val0 << 120 * << 121 * if (store_ptr == {a2}) << 122 * break; << 123 * << 124 * load_val0 = load_ptr[2]; << 125 * load_ptr += 2; << 126 * store_ptr[1 - 2] = (load_val1 << 127 * << 128 * } while (store_ptr != store_ptr_end << 129 * store_ptr = store_ptr_end; << 130 */ << 131 << 132 REG_L t0, (0 * SZREG)(a1) << 133 1: << 134 REG_L t1, (1 * SZREG)(a1) << 135 addi t3, t3, (2 * SZREG) << 136 srl t0, t0, a6 << 137 sll t2, t1, a7 << 138 or t2, t0, t2 << 139 REG_S t2, ((0 * SZREG) - (2 * SZREG))( << 140 << 141 beq t3, a2, 2f << 142 << 143 REG_L t0, (2 * SZREG)(a1) << 144 addi a1, a1, (2 * SZREG) << 145 srl t1, t1, a6 << 146 sll t2, t0, a7 << 147 or t2, t1, t2 << 148 REG_S t2, ((1 * SZREG) - (2 * SZREG))( << 149 << 150 bne t3, t6, 1b << 151 2: << 152 mv t3, t6 /* Fix the dest pointer i << 153 << 154 add a1, t3, a5 /* Restore the src poi << 155 j .Lbyte_copy_forward /* Copy any rema << 156 << 157 .Lmisaligned_fixup_copy_reverse: << 158 jal t0, .Lbyte_copy_until_aligned_rev << 159 << 160 andi a5, a4, (SZREG - 1) /* Find the a << 161 slli a6, a5, 3 /* Multiply by 8 to con << 162 sub a5, a4, t4 /* Find the difference << 163 andi a4, a4, -SZREG /* Align the src p << 164 addi a2, t5, -SZREG /* The other break << 165 << 166 /* << 167 * Compute The Inverse Shift << 168 * a7 = XLEN - a6 = XLEN + -a6 << 169 * 2s complement negation to find the << 170 * Add that to XLEN. XLEN = SZREG * 8 << 171 */ << 172 not a7, a6 << 173 addi a7, a7, (SZREG * 8 + 1) << 174 << 175 /* << 176 * Fix Misalignment Copy Loop - Revers << 177 * load_val1 = load_ptr[0]; << 178 * do { << 179 * load_val0 = load_ptr[-1]; << 180 * store_ptr -= 2; << 181 * store_ptr[1] = (load_val0 >> { << 182 * << 183 * if (store_ptr == {a2}) << 184 * break; << 185 * << 186 * load_val1 = load_ptr[-2]; << 187 * load_ptr -= 2; << 188 * store_ptr[0] = (load_val1 >> { << 189 * << 190 * } while (store_ptr != store_ptr_end << 191 * store_ptr = store_ptr_end; << 192 */ << 193 << 194 REG_L t1, ( 0 * SZREG)(a4) << 195 1: << 196 REG_L t0, (-1 * SZREG)(a4) << 197 addi t4, t4, (-2 * SZREG) << 198 sll t1, t1, a7 << 199 srl t2, t0, a6 << 200 or t2, t1, t2 << 201 REG_S t2, ( 1 * SZREG)(t4) << 202 << 203 beq t4, a2, 2f << 204 << 205 REG_L t1, (-2 * SZREG)(a4) << 206 addi a4, a4, (-2 * SZREG) << 207 sll t0, t0, a7 << 208 srl t2, t1, a6 << 209 or t2, t0, t2 << 210 REG_S t2, ( 0 * SZREG)(t4) << 211 << 212 bne t4, t5, 1b << 213 2: << 214 mv t4, t5 /* Fix the dest pointer i << 215 << 216 add a4, t4, a5 /* Restore the src poi << 217 j .Lbyte_copy_reverse /* Copy any rema << 218 << 219 /* << 220 * Simple copy loops for SZREG co-aligned memo << 221 * These also make calls to do byte copies for << 222 * data at their terminations. << 223 */ << 224 .Lcoaligned_copy: << 225 bltu a1, a0, .Lcoaligned_copy_reverse << 226 << 227 .Lcoaligned_copy_forward: << 228 jal t0, .Lbyte_copy_until_aligned_forw << 229 << 230 1: << 231 REG_L t1, ( 0 * SZREG)(a1) << 232 addi a1, a1, SZREG << 233 addi t3, t3, SZREG << 234 REG_S t1, (-1 * SZREG)(t3) << 235 bne t3, t6, 1b << 236 << 237 j .Lbyte_copy_forward /* Copy any rema << 238 << 239 .Lcoaligned_copy_reverse: << 240 jal t0, .Lbyte_copy_until_aligned_reve << 241 << 242 1: << 243 REG_L t1, (-1 * SZREG)(a4) << 244 addi a4, a4, -SZREG << 245 addi t4, t4, -SZREG << 246 REG_S t1, ( 0 * SZREG)(t4) << 247 bne t4, t5, 1b << 248 << 249 j .Lbyte_copy_reverse /* Copy any rema << 250 << 251 /* << 252 * These are basically sub-functions within th << 253 * are used to byte copy until the dest pointe << 254 * At which point, a bulk copy method can be u << 255 * calling code. These work on the same regis << 256 * copy loops. Therefore, the register values << 257 * up from where they were left and we avoid c << 258 * without any overhead except the call in and << 259 */ << 260 .Lbyte_copy_until_aligned_forward: << 261 beq t3, t5, 2f << 262 1: << 263 lb t1, 0(a1) << 264 addi a1, a1, 1 << 265 addi t3, t3, 1 << 266 sb t1, -1(t3) << 267 bne t3, t5, 1b << 268 2: << 269 jalr zero, 0x0(t0) /* Return to multib << 270 << 271 .Lbyte_copy_until_aligned_reverse: << 272 beq t4, t6, 2f << 273 1: << 274 lb t1, -1(a4) << 275 addi a4, a4, -1 << 276 addi t4, t4, -1 << 277 sb t1, 0(t4) << 278 bne t4, t6, 1b << 279 2: << 280 jalr zero, 0x0(t0) /* Return to multib << 281 << 282 /* << 283 * Simple byte copy loops. << 284 * These will byte copy until they reach the e << 285 * At that point, they will call to return fro << 286 */ << 287 .Lbyte_copy: << 288 bltu a1, a0, .Lbyte_copy_reverse << 289 << 290 .Lbyte_copy_forward: << 291 beq t3, t4, 2f << 292 1: << 293 lb t1, 0(a1) << 294 addi a1, a1, 1 << 295 addi t3, t3, 1 << 296 sb t1, -1(t3) << 297 bne t3, t4, 1b << 298 2: << 299 ret << 300 << 301 .Lbyte_copy_reverse: << 302 beq t4, t3, 2f << 303 1: << 304 lb t1, -1(a4) << 305 addi a4, a4, -1 << 306 addi t4, t4, -1 << 307 sb t1, 0(t4) << 308 bne t4, t3, 1b << 309 2: << 310 << 311 .Lreturn_from_memmove: << 312 ret << 313 << 314 SYM_FUNC_END(__memmove) << 315 SYM_FUNC_ALIAS_WEAK(memmove, __memmove) << 316 SYM_FUNC_ALIAS(__pi_memmove, __memmove) << 317 SYM_FUNC_ALIAS(__pi___memmove, __memmove) <<

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

TOMOYO Linux Cross Reference
Linux/arch/riscv/lib/memmove.S

Diff markup

Differences between /arch/riscv/lib/memmove.S (Version linux-6.12-rc7) and /arch/sparc/lib/memmove.S (Version linux-6.10.14)

TOMOYO Linux Cross Reference Linux/arch/riscv/lib/memmove.S

Diff markup

Differences between /arch/riscv/lib/memmove.S (Version linux-6.12-rc7) and /arch/sparc/lib/memmove.S (Version linux-6.10.14)

TOMOYO Linux Cross Reference
Linux/arch/riscv/lib/memmove.S