| /* |
| * linux/arch/arm/lib/copy_template.s |
| * |
| * Code template for optimized memory copy functions |
| * |
| * Author: Nicolas Pitre |
| * Created: Sep 28, 2005 |
| * Copyright: MontaVista Software, Inc. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| /* |
| * Theory of operation |
| * ------------------- |
| * |
| * This file provides the core code for a forward memory copy used in |
| * the implementation of memcopy(), copy_to_user() and copy_from_user(). |
| * |
| * The including file must define the following accessor macros |
| * according to the need of the given function: |
| * |
| * ldr1w ptr reg abort |
| * |
| * This loads one word from 'ptr', stores it in 'reg' and increments |
| * 'ptr' to the next word. The 'abort' argument is used for fixup tables. |
| * |
| * ldr4w ptr reg1 reg2 reg3 reg4 abort |
| * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort |
| * |
| * This loads four or eight words starting from 'ptr', stores them |
| * in provided registers and increments 'ptr' past those words. |
| * The'abort' argument is used for fixup tables. |
| * |
| * ldr1b ptr reg cond abort |
| * |
| * Similar to ldr1w, but it loads a byte and increments 'ptr' one byte. |
| * It also must apply the condition code if provided, otherwise the |
| * "al" condition is assumed by default. |
| * |
| * str1w ptr reg abort |
| * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort |
| * str1b ptr reg cond abort |
| * |
| * Same as their ldr* counterparts, but data is stored to 'ptr' location |
| * rather than being loaded. |
| * |
| * enter reg1 reg2 |
| * |
| * Preserve the provided registers on the stack plus any additional |
| * data as needed by the implementation including this code. Called |
| * upon code entry. |
| * |
| * usave reg1 reg2 |
| * |
| * Unwind annotation macro is corresponding for 'enter' macro. |
| * It tell unwinder that preserved some provided registers on the stack |
| * and additional data by a prior 'enter' macro. |
| * |
| * exit reg1 reg2 |
| * |
| * Restore registers with the values previously saved with the |
| * 'preserv' macro. Called upon code termination. |
| * |
| * LDR1W_SHIFT |
| * STR1W_SHIFT |
| * |
| * Correction to be applied to the "ip" register when branching into |
| * the ldr1w or str1w instructions (some of these macros may expand to |
| * than one 32bit instruction in Thumb-2) |
| */ |
| |
| |
| UNWIND( .fnstart ) |
| enter r4, lr |
| UNWIND( .fnend ) |
| |
| UNWIND( .fnstart ) |
| usave r4, lr @ in first stmdb block |
| |
| subs r2, r2, #4 |
| blt 8f |
| ands ip, r0, #3 |
| PLD( pld [r1, #0] ) |
| bne 9f |
| ands ip, r1, #3 |
| bne 10f |
| |
| 1: subs r2, r2, #(28) |
| stmfd sp!, {r5 - r8} |
| UNWIND( .fnend ) |
| |
| UNWIND( .fnstart ) |
| usave r4, lr |
| UNWIND( .save {r5 - r8} ) @ in second stmfd block |
| blt 5f |
| |
| CALGN( ands ip, r0, #31 ) |
| CALGN( rsb r3, ip, #32 ) |
| CALGN( sbcnes r4, r3, r2 ) @ C is always set here |
| CALGN( bcs 2f ) |
| CALGN( adr r4, 6f ) |
| CALGN( subs r2, r2, r3 ) @ C gets set |
| CALGN( add pc, r4, ip ) |
| |
| PLD( pld [r1, #0] ) |
| 2: PLD( subs r2, r2, #96 ) |
| PLD( pld [r1, #28] ) |
| PLD( blt 4f ) |
| PLD( pld [r1, #60] ) |
| PLD( pld [r1, #92] ) |
| |
| 3: PLD( pld [r1, #124] ) |
| 4: ldr8w r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f |
| subs r2, r2, #32 |
| str8w r0, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f |
| bge 3b |
| PLD( cmn r2, #96 ) |
| PLD( bge 4b ) |
| |
| 5: ands ip, r2, #28 |
| rsb ip, ip, #32 |
| #if LDR1W_SHIFT > 0 |
| lsl ip, ip, #LDR1W_SHIFT |
| #endif |
| addne pc, pc, ip @ C is always clear here |
| b 7f |
| 6: |
| .rept (1 << LDR1W_SHIFT) |
| W(nop) |
| .endr |
| ldr1w r1, r3, abort=20f |
| ldr1w r1, r4, abort=20f |
| ldr1w r1, r5, abort=20f |
| ldr1w r1, r6, abort=20f |
| ldr1w r1, r7, abort=20f |
| ldr1w r1, r8, abort=20f |
| ldr1w r1, lr, abort=20f |
| |
| #if LDR1W_SHIFT < STR1W_SHIFT |
| lsl ip, ip, #STR1W_SHIFT - LDR1W_SHIFT |
| #elif LDR1W_SHIFT > STR1W_SHIFT |
| lsr ip, ip, #LDR1W_SHIFT - STR1W_SHIFT |
| #endif |
| add pc, pc, ip |
| nop |
| .rept (1 << STR1W_SHIFT) |
| W(nop) |
| .endr |
| str1w r0, r3, abort=20f |
| str1w r0, r4, abort=20f |
| str1w r0, r5, abort=20f |
| str1w r0, r6, abort=20f |
| str1w r0, r7, abort=20f |
| str1w r0, r8, abort=20f |
| str1w r0, lr, abort=20f |
| |
| CALGN( bcs 2b ) |
| |
| 7: ldmfd sp!, {r5 - r8} |
| UNWIND( .fnend ) @ end of second stmfd block |
| |
| UNWIND( .fnstart ) |
| usave r4, lr @ still in first stmdb block |
| 8: movs r2, r2, lsl #31 |
| ldr1b r1, r3, ne, abort=21f |
| ldr1b r1, r4, cs, abort=21f |
| ldr1b r1, ip, cs, abort=21f |
| str1b r0, r3, ne, abort=21f |
| str1b r0, r4, cs, abort=21f |
| str1b r0, ip, cs, abort=21f |
| |
| exit r4, pc |
| |
| 9: rsb ip, ip, #4 |
| cmp ip, #2 |
| ldr1b r1, r3, gt, abort=21f |
| ldr1b r1, r4, ge, abort=21f |
| ldr1b r1, lr, abort=21f |
| str1b r0, r3, gt, abort=21f |
| str1b r0, r4, ge, abort=21f |
| subs r2, r2, ip |
| str1b r0, lr, abort=21f |
| blt 8b |
| ands ip, r1, #3 |
| beq 1b |
| |
| 10: bic r1, r1, #3 |
| cmp ip, #2 |
| ldr1w r1, lr, abort=21f |
| beq 17f |
| bgt 18f |
| UNWIND( .fnend ) |
| |
| |
| .macro forward_copy_shift pull push |
| |
| UNWIND( .fnstart ) |
| usave r4, lr @ still in first stmdb block |
| subs r2, r2, #28 |
| blt 14f |
| |
| CALGN( ands ip, r0, #31 ) |
| CALGN( rsb ip, ip, #32 ) |
| CALGN( sbcnes r4, ip, r2 ) @ C is always set here |
| CALGN( subcc r2, r2, ip ) |
| CALGN( bcc 15f ) |
| |
| 11: stmfd sp!, {r5 - r9} |
| UNWIND( .fnend ) |
| |
| UNWIND( .fnstart ) |
| usave r4, lr |
| UNWIND( .save {r5 - r9} ) @ in new second stmfd block |
| PLD( pld [r1, #0] ) |
| PLD( subs r2, r2, #96 ) |
| PLD( pld [r1, #28] ) |
| PLD( blt 13f ) |
| PLD( pld [r1, #60] ) |
| PLD( pld [r1, #92] ) |
| |
| 12: PLD( pld [r1, #124] ) |
| 13: ldr4w r1, r4, r5, r6, r7, abort=19f |
| mov r3, lr, lspull #\pull |
| subs r2, r2, #32 |
| ldr4w r1, r8, r9, ip, lr, abort=19f |
| orr r3, r3, r4, lspush #\push |
| mov r4, r4, lspull #\pull |
| orr r4, r4, r5, lspush #\push |
| mov r5, r5, lspull #\pull |
| orr r5, r5, r6, lspush #\push |
| mov r6, r6, lspull #\pull |
| orr r6, r6, r7, lspush #\push |
| mov r7, r7, lspull #\pull |
| orr r7, r7, r8, lspush #\push |
| mov r8, r8, lspull #\pull |
| orr r8, r8, r9, lspush #\push |
| mov r9, r9, lspull #\pull |
| orr r9, r9, ip, lspush #\push |
| mov ip, ip, lspull #\pull |
| orr ip, ip, lr, lspush #\push |
| str8w r0, r3, r4, r5, r6, r7, r8, r9, ip, , abort=19f |
| bge 12b |
| PLD( cmn r2, #96 ) |
| PLD( bge 13b ) |
| |
| ldmfd sp!, {r5 - r9} |
| UNWIND( .fnend ) @ end of the second stmfd block |
| |
| UNWIND( .fnstart ) |
| usave r4, lr @ still in first stmdb block |
| 14: ands ip, r2, #28 |
| beq 16f |
| |
| 15: mov r3, lr, lspull #\pull |
| ldr1w r1, lr, abort=21f |
| subs ip, ip, #4 |
| orr r3, r3, lr, lspush #\push |
| str1w r0, r3, abort=21f |
| bgt 15b |
| CALGN( cmp r2, #0 ) |
| CALGN( bge 11b ) |
| |
| 16: sub r1, r1, #(\push / 8) |
| b 8b |
| UNWIND( .fnend ) |
| |
| .endm |
| |
| |
| forward_copy_shift pull=8 push=24 |
| |
| 17: forward_copy_shift pull=16 push=16 |
| |
| 18: forward_copy_shift pull=24 push=8 |
| |
| |
| /* |
| * Abort preamble and completion macros. |
| * If a fixup handler is required then those macros must surround it. |
| * It is assumed that the fixup code will handle the private part of |
| * the exit macro. |
| */ |
| |
| .macro copy_abort_preamble |
| 19: ldmfd sp!, {r5 - r9} |
| b 21f |
| 20: ldmfd sp!, {r5 - r8} |
| 21: |
| .endm |
| |
| .macro copy_abort_end |
| ldmfd sp!, {r4, pc} |
| .endm |
| |
