Sync the libgcc 32bit division and modulo operations with Linux 4.4.6 , commit 0d1912303e54ed1b2a371be0bba51c384dd57326 . The functions in these four files are present in lib1funcs.S in Linux, so replace these files with lib1funcs.S from Linux.
Since we do not support stack unwinding, instead of importing the whole asm/unwind.h and all the baggage, this patch defines empty UNWIND() macro in lib1funcs.S . Moreover, to make all of the functions available, define CONFIG_AEABI , which is safe, because U-Boot is always compiled with ARM EABI.
This patch also defines CONFIG_THUMB2_KERNEL and CONFIG_ARM_ASM_UNIFIED which is necessary for correct build of these files both in ARM and Thumb mode, just like Linux does.
Signed-off-by: Marek Vasut marex@denx.de Cc: Albert Aribaud albert.u.boot@aribaud.net Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Simon Glass sjg@chromium.org Cc: Tom Rini trini@konsulko.com --- arch/arm/lib/Makefile | 5 +- arch/arm/lib/divsi3.S | 143 ------------------- arch/arm/lib/lib1funcs.S | 351 +++++++++++++++++++++++++++++++++++++++++++++++ arch/arm/lib/modsi3.S | 99 ------------- arch/arm/lib/udivsi3.S | 95 ------------- arch/arm/lib/umodsi3.S | 90 ------------ 6 files changed, 353 insertions(+), 430 deletions(-) delete mode 100644 arch/arm/lib/divsi3.S create mode 100644 arch/arm/lib/lib1funcs.S delete mode 100644 arch/arm/lib/modsi3.S delete mode 100644 arch/arm/lib/udivsi3.S delete mode 100644 arch/arm/lib/umodsi3.S
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index cafd94d..0b0dbcb 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -5,9 +5,8 @@ # SPDX-License-Identifier: GPL-2.0+ #
-lib-$(CONFIG_USE_PRIVATE_LIBGCC) += ashldi3.o ashrdi3.o divsi3.o \ - lshrdi3.o modsi3.o udivsi3.o umodsi3.o div0.o \ - uldivmod.o +lib-$(CONFIG_USE_PRIVATE_LIBGCC) += ashldi3.o ashrdi3.o lshrdi3.o \ + lib1funcs.o uldivmod.o div0.o
ifdef CONFIG_CPU_V7M obj-y += vectors_m.o crt0.o diff --git a/arch/arm/lib/divsi3.S b/arch/arm/lib/divsi3.S deleted file mode 100644 index c463c68..0000000 --- a/arch/arm/lib/divsi3.S +++ /dev/null @@ -1,143 +0,0 @@ -#include <linux/linkage.h> - -.macro ARM_DIV_BODY dividend, divisor, result, curbit - -#if __LINUX_ARM_ARCH__ >= 5 - - clz \curbit, \divisor - clz \result, \dividend - sub \result, \curbit, \result - mov \curbit, #1 - mov \divisor, \divisor, lsl \result - mov \curbit, \curbit, lsl \result - mov \result, #0 - -#else - - @ Initially shift the divisor left 3 bits if possible, - @ set curbit accordingly. This allows for curbit to be located - @ at the left end of each 4 bit nibbles in the division loop - @ to save one loop in most cases. - tst \divisor, #0xe0000000 - moveq \divisor, \divisor, lsl #3 - moveq \curbit, #8 - movne \curbit, #1 - - @ Unless the divisor is very big, shift it up in multiples of - @ four bits, since this is the amount of unwinding in the main - @ division loop. Continue shifting until the divisor is - @ larger than the dividend. -1: cmp \divisor, #0x10000000 - cmplo \divisor, \dividend - movlo \divisor, \divisor, lsl #4 - movlo \curbit, \curbit, lsl #4 - blo 1b - - @ For very big divisors, we must shift it a bit at a time, or - @ we will be in danger of overflowing. -1: cmp \divisor, #0x80000000 - cmplo \divisor, \dividend - movlo \divisor, \divisor, lsl #1 - movlo \curbit, \curbit, lsl #1 - blo 1b - - mov \result, #0 - -#endif - - @ Division loop -1: cmp \dividend, \divisor - subhs \dividend, \dividend, \divisor - orrhs \result, \result, \curbit - cmp \dividend, \divisor, lsr #1 - subhs \dividend, \dividend, \divisor, lsr #1 - orrhs \result, \result, \curbit, lsr #1 - cmp \dividend, \divisor, lsr #2 - subhs \dividend, \dividend, \divisor, lsr #2 - orrhs \result, \result, \curbit, lsr #2 - cmp \dividend, \divisor, lsr #3 - subhs \dividend, \dividend, \divisor, lsr #3 - orrhs \result, \result, \curbit, lsr #3 - cmp \dividend, #0 @ Early termination? - movnes \curbit, \curbit, lsr #4 @ No, any more bits to do? - movne \divisor, \divisor, lsr #4 - bne 1b - -.endm - -.macro ARM_DIV2_ORDER divisor, order - -#if __LINUX_ARM_ARCH__ >= 5 - - clz \order, \divisor - rsb \order, \order, #31 - -#else - - cmp \divisor, #(1 << 16) - movhs \divisor, \divisor, lsr #16 - movhs \order, #16 - movlo \order, #0 - - cmp \divisor, #(1 << 8) - movhs \divisor, \divisor, lsr #8 - addhs \order, \order, #8 - - cmp \divisor, #(1 << 4) - movhs \divisor, \divisor, lsr #4 - addhs \order, \order, #4 - - cmp \divisor, #(1 << 2) - addhi \order, \order, #3 - addls \order, \order, \divisor, lsr #1 - -#endif - -.endm - - .align 5 -.globl __divsi3 -__divsi3: -ENTRY(__aeabi_idiv) - cmp r1, #0 - eor ip, r0, r1 @ save the sign of the result. - beq Ldiv0 - rsbmi r1, r1, #0 @ loops below use unsigned. - subs r2, r1, #1 @ division by 1 or -1 ? - beq 10f - movs r3, r0 - rsbmi r3, r0, #0 @ positive dividend value - cmp r3, r1 - bls 11f - tst r1, r2 @ divisor is power of 2 ? - beq 12f - - ARM_DIV_BODY r3, r1, r0, r2 - - cmp ip, #0 - rsbmi r0, r0, #0 - mov pc, lr - -10: teq ip, r0 @ same sign ? - rsbmi r0, r0, #0 - mov pc, lr - -11: movlo r0, #0 - moveq r0, ip, asr #31 - orreq r0, r0, #1 - mov pc, lr - -12: ARM_DIV2_ORDER r1, r2 - - cmp ip, #0 - mov r0, r3, lsr r2 - rsbmi r0, r0, #0 - mov pc, lr - -Ldiv0: - - str lr, [sp, #-4]! - bl __div0 - mov r0, #0 @ About as wrong as it could be. - ldr pc, [sp], #4 -ENDPROC(__aeabi_idiv) diff --git a/arch/arm/lib/lib1funcs.S b/arch/arm/lib/lib1funcs.S new file mode 100644 index 0000000..5871dbe --- /dev/null +++ b/arch/arm/lib/lib1funcs.S @@ -0,0 +1,351 @@ +/* + * linux/arch/arm/lib/lib1funcs.S: Optimized ARM division routines + * + * Author: Nicolas Pitre nico@fluxnic.net + * - contributed to gcc-3.4 on Sep 30, 2003 + * - adapted for the Linux kernel on Oct 2, 2003 + */ + +/* Copyright 1995, 1996, 1998, 1999, 2000, 2003 Free Software Foundation, Inc. + + * SPDX-License-Identifier: GPL-2.0+ + */ + + +#include <linux/linkage.h> +#include <asm/assembler.h> + +/* + * U-Boot compatibility bit, define empty UNWIND() macro as, since we + * do not support stack unwinding and define CONFIG_AEABI to make all + * of the functions available without diverging from Linux code. + */ +#ifdef __UBOOT__ +#define UNWIND(x...) +#define CONFIG_AEABI +#endif + +.macro ARM_DIV_BODY dividend, divisor, result, curbit + +#if __LINUX_ARM_ARCH__ >= 5 + + clz \curbit, \divisor + clz \result, \dividend + sub \result, \curbit, \result + mov \curbit, #1 + mov \divisor, \divisor, lsl \result + mov \curbit, \curbit, lsl \result + mov \result, #0 + +#else + + @ Initially shift the divisor left 3 bits if possible, + @ set curbit accordingly. This allows for curbit to be located + @ at the left end of each 4 bit nibbles in the division loop + @ to save one loop in most cases. + tst \divisor, #0xe0000000 + moveq \divisor, \divisor, lsl #3 + moveq \curbit, #8 + movne \curbit, #1 + + @ Unless the divisor is very big, shift it up in multiples of + @ four bits, since this is the amount of unwinding in the main + @ division loop. Continue shifting until the divisor is + @ larger than the dividend. +1: cmp \divisor, #0x10000000 + cmplo \divisor, \dividend + movlo \divisor, \divisor, lsl #4 + movlo \curbit, \curbit, lsl #4 + blo 1b + + @ For very big divisors, we must shift it a bit at a time, or + @ we will be in danger of overflowing. +1: cmp \divisor, #0x80000000 + cmplo \divisor, \dividend + movlo \divisor, \divisor, lsl #1 + movlo \curbit, \curbit, lsl #1 + blo 1b + + mov \result, #0 + +#endif + + @ Division loop +1: cmp \dividend, \divisor + subhs \dividend, \dividend, \divisor + orrhs \result, \result, \curbit + cmp \dividend, \divisor, lsr #1 + subhs \dividend, \dividend, \divisor, lsr #1 + orrhs \result, \result, \curbit, lsr #1 + cmp \dividend, \divisor, lsr #2 + subhs \dividend, \dividend, \divisor, lsr #2 + orrhs \result, \result, \curbit, lsr #2 + cmp \dividend, \divisor, lsr #3 + subhs \dividend, \dividend, \divisor, lsr #3 + orrhs \result, \result, \curbit, lsr #3 + cmp \dividend, #0 @ Early termination? + movnes \curbit, \curbit, lsr #4 @ No, any more bits to do? + movne \divisor, \divisor, lsr #4 + bne 1b + +.endm + + +.macro ARM_DIV2_ORDER divisor, order + +#if __LINUX_ARM_ARCH__ >= 5 + + clz \order, \divisor + rsb \order, \order, #31 + +#else + + cmp \divisor, #(1 << 16) + movhs \divisor, \divisor, lsr #16 + movhs \order, #16 + movlo \order, #0 + + cmp \divisor, #(1 << 8) + movhs \divisor, \divisor, lsr #8 + addhs \order, \order, #8 + + cmp \divisor, #(1 << 4) + movhs \divisor, \divisor, lsr #4 + addhs \order, \order, #4 + + cmp \divisor, #(1 << 2) + addhi \order, \order, #3 + addls \order, \order, \divisor, lsr #1 + +#endif + +.endm + + +.macro ARM_MOD_BODY dividend, divisor, order, spare + +#if __LINUX_ARM_ARCH__ >= 5 + + clz \order, \divisor + clz \spare, \dividend + sub \order, \order, \spare + mov \divisor, \divisor, lsl \order + +#else + + mov \order, #0 + + @ Unless the divisor is very big, shift it up in multiples of + @ four bits, since this is the amount of unwinding in the main + @ division loop. Continue shifting until the divisor is + @ larger than the dividend. +1: cmp \divisor, #0x10000000 + cmplo \divisor, \dividend + movlo \divisor, \divisor, lsl #4 + addlo \order, \order, #4 + blo 1b + + @ For very big divisors, we must shift it a bit at a time, or + @ we will be in danger of overflowing. +1: cmp \divisor, #0x80000000 + cmplo \divisor, \dividend + movlo \divisor, \divisor, lsl #1 + addlo \order, \order, #1 + blo 1b + +#endif + + @ Perform all needed subtractions to keep only the reminder. + @ Do comparisons in batch of 4 first. + subs \order, \order, #3 @ yes, 3 is intended here + blt 2f + +1: cmp \dividend, \divisor + subhs \dividend, \dividend, \divisor + cmp \dividend, \divisor, lsr #1 + subhs \dividend, \dividend, \divisor, lsr #1 + cmp \dividend, \divisor, lsr #2 + subhs \dividend, \dividend, \divisor, lsr #2 + cmp \dividend, \divisor, lsr #3 + subhs \dividend, \dividend, \divisor, lsr #3 + cmp \dividend, #1 + mov \divisor, \divisor, lsr #4 + subges \order, \order, #4 + bge 1b + + tst \order, #3 + teqne \dividend, #0 + beq 5f + + @ Either 1, 2 or 3 comparison/subtractions are left. +2: cmn \order, #2 + blt 4f + beq 3f + cmp \dividend, \divisor + subhs \dividend, \dividend, \divisor + mov \divisor, \divisor, lsr #1 +3: cmp \dividend, \divisor + subhs \dividend, \dividend, \divisor + mov \divisor, \divisor, lsr #1 +4: cmp \dividend, \divisor + subhs \dividend, \dividend, \divisor +5: +.endm + + +ENTRY(__udivsi3) +ENTRY(__aeabi_uidiv) +UNWIND(.fnstart) + + subs r2, r1, #1 + reteq lr + bcc Ldiv0 + cmp r0, r1 + bls 11f + tst r1, r2 + beq 12f + + ARM_DIV_BODY r0, r1, r2, r3 + + mov r0, r2 + ret lr + +11: moveq r0, #1 + movne r0, #0 + ret lr + +12: ARM_DIV2_ORDER r1, r2 + + mov r0, r0, lsr r2 + ret lr + +UNWIND(.fnend) +ENDPROC(__udivsi3) +ENDPROC(__aeabi_uidiv) + +ENTRY(__umodsi3) +UNWIND(.fnstart) + + subs r2, r1, #1 @ compare divisor with 1 + bcc Ldiv0 + cmpne r0, r1 @ compare dividend with divisor + moveq r0, #0 + tsthi r1, r2 @ see if divisor is power of 2 + andeq r0, r0, r2 + retls lr + + ARM_MOD_BODY r0, r1, r2, r3 + + ret lr + +UNWIND(.fnend) +ENDPROC(__umodsi3) + +ENTRY(__divsi3) +ENTRY(__aeabi_idiv) +UNWIND(.fnstart) + + cmp r1, #0 + eor ip, r0, r1 @ save the sign of the result. + beq Ldiv0 + rsbmi r1, r1, #0 @ loops below use unsigned. + subs r2, r1, #1 @ division by 1 or -1 ? + beq 10f + movs r3, r0 + rsbmi r3, r0, #0 @ positive dividend value + cmp r3, r1 + bls 11f + tst r1, r2 @ divisor is power of 2 ? + beq 12f + + ARM_DIV_BODY r3, r1, r0, r2 + + cmp ip, #0 + rsbmi r0, r0, #0 + ret lr + +10: teq ip, r0 @ same sign ? + rsbmi r0, r0, #0 + ret lr + +11: movlo r0, #0 + moveq r0, ip, asr #31 + orreq r0, r0, #1 + ret lr + +12: ARM_DIV2_ORDER r1, r2 + + cmp ip, #0 + mov r0, r3, lsr r2 + rsbmi r0, r0, #0 + ret lr + +UNWIND(.fnend) +ENDPROC(__divsi3) +ENDPROC(__aeabi_idiv) + +ENTRY(__modsi3) +UNWIND(.fnstart) + + cmp r1, #0 + beq Ldiv0 + rsbmi r1, r1, #0 @ loops below use unsigned. + movs ip, r0 @ preserve sign of dividend + rsbmi r0, r0, #0 @ if negative make positive + subs r2, r1, #1 @ compare divisor with 1 + cmpne r0, r1 @ compare dividend with divisor + moveq r0, #0 + tsthi r1, r2 @ see if divisor is power of 2 + andeq r0, r0, r2 + bls 10f + + ARM_MOD_BODY r0, r1, r2, r3 + +10: cmp ip, #0 + rsbmi r0, r0, #0 + ret lr + +UNWIND(.fnend) +ENDPROC(__modsi3) + +#ifdef CONFIG_AEABI + +ENTRY(__aeabi_uidivmod) +UNWIND(.fnstart) +UNWIND(.save {r0, r1, ip, lr} ) + + stmfd sp!, {r0, r1, ip, lr} + bl __aeabi_uidiv + ldmfd sp!, {r1, r2, ip, lr} + mul r3, r0, r2 + sub r1, r1, r3 + ret lr + +UNWIND(.fnend) +ENDPROC(__aeabi_uidivmod) + +ENTRY(__aeabi_idivmod) +UNWIND(.fnstart) +UNWIND(.save {r0, r1, ip, lr} ) + stmfd sp!, {r0, r1, ip, lr} + bl __aeabi_idiv + ldmfd sp!, {r1, r2, ip, lr} + mul r3, r0, r2 + sub r1, r1, r3 + ret lr + +UNWIND(.fnend) +ENDPROC(__aeabi_idivmod) + +#endif + +Ldiv0: +UNWIND(.fnstart) +UNWIND(.pad #4) +UNWIND(.save {lr}) + str lr, [sp, #-8]! + bl __div0 + mov r0, #0 @ About as wrong as it could be. + ldr pc, [sp], #8 +UNWIND(.fnend) +ENDPROC(Ldiv0) diff --git a/arch/arm/lib/modsi3.S b/arch/arm/lib/modsi3.S deleted file mode 100644 index c5e1c22..0000000 --- a/arch/arm/lib/modsi3.S +++ /dev/null @@ -1,99 +0,0 @@ -#include <linux/linkage.h> - -.macro ARM_MOD_BODY dividend, divisor, order, spare - -#if __LINUX_ARM_ARCH__ >= 5 - - clz \order, \divisor - clz \spare, \dividend - sub \order, \order, \spare - mov \divisor, \divisor, lsl \order - -#else - - mov \order, #0 - - @ Unless the divisor is very big, shift it up in multiples of - @ four bits, since this is the amount of unwinding in the main - @ division loop. Continue shifting until the divisor is - @ larger than the dividend. -1: cmp \divisor, #0x10000000 - cmplo \divisor, \dividend - movlo \divisor, \divisor, lsl #4 - addlo \order, \order, #4 - blo 1b - - @ For very big divisors, we must shift it a bit at a time, or - @ we will be in danger of overflowing. -1: cmp \divisor, #0x80000000 - cmplo \divisor, \dividend - movlo \divisor, \divisor, lsl #1 - addlo \order, \order, #1 - blo 1b - -#endif - - @ Perform all needed substractions to keep only the reminder. - @ Do comparisons in batch of 4 first. - subs \order, \order, #3 @ yes, 3 is intended here - blt 2f - -1: cmp \dividend, \divisor - subhs \dividend, \dividend, \divisor - cmp \dividend, \divisor, lsr #1 - subhs \dividend, \dividend, \divisor, lsr #1 - cmp \dividend, \divisor, lsr #2 - subhs \dividend, \dividend, \divisor, lsr #2 - cmp \dividend, \divisor, lsr #3 - subhs \dividend, \dividend, \divisor, lsr #3 - cmp \dividend, #1 - mov \divisor, \divisor, lsr #4 - subges \order, \order, #4 - bge 1b - - tst \order, #3 - teqne \dividend, #0 - beq 5f - - @ Either 1, 2 or 3 comparison/substractions are left. -2: cmn \order, #2 - blt 4f - beq 3f - cmp \dividend, \divisor - subhs \dividend, \dividend, \divisor - mov \divisor, \divisor, lsr #1 -3: cmp \dividend, \divisor - subhs \dividend, \dividend, \divisor - mov \divisor, \divisor, lsr #1 -4: cmp \dividend, \divisor - subhs \dividend, \dividend, \divisor -5: -.endm - - .align 5 -ENTRY(__modsi3) - cmp r1, #0 - beq Ldiv0 - rsbmi r1, r1, #0 @ loops below use unsigned. - movs ip, r0 @ preserve sign of dividend - rsbmi r0, r0, #0 @ if negative make positive - subs r2, r1, #1 @ compare divisor with 1 - cmpne r0, r1 @ compare dividend with divisor - moveq r0, #0 - tsthi r1, r2 @ see if divisor is power of 2 - andeq r0, r0, r2 - bls 10f - - ARM_MOD_BODY r0, r1, r2, r3 - -10: cmp ip, #0 - rsbmi r0, r0, #0 - mov pc, lr -ENDPROC(__modsi3) - -Ldiv0: - - str lr, [sp, #-4]! - bl __div0 - mov r0, #0 @ About as wrong as it could be. - ldr pc, [sp], #4 diff --git a/arch/arm/lib/udivsi3.S b/arch/arm/lib/udivsi3.S deleted file mode 100644 index 3b653be..0000000 --- a/arch/arm/lib/udivsi3.S +++ /dev/null @@ -1,95 +0,0 @@ -#include <linux/linkage.h> - -/* # 1 "libgcc1.S" */ -@ libgcc1 routines for ARM cpu. -@ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk) -dividend .req r0 -divisor .req r1 -result .req r2 -curbit .req r3 -/* ip .req r12 */ -/* sp .req r13 */ -/* lr .req r14 */ -/* pc .req r15 */ - .text - .globl __udivsi3 - .type __udivsi3 ,function - .globl __aeabi_uidiv - .type __aeabi_uidiv ,function - .align 0 - __udivsi3: - __aeabi_uidiv: - cmp divisor, #0 - beq Ldiv0 - mov curbit, #1 - mov result, #0 - cmp dividend, divisor - bcc Lgot_result -Loop1: - @ Unless the divisor is very big, shift it up in multiples of - @ four bits, since this is the amount of unwinding in the main - @ division loop. Continue shifting until the divisor is - @ larger than the dividend. - cmp divisor, #0x10000000 - cmpcc divisor, dividend - movcc divisor, divisor, lsl #4 - movcc curbit, curbit, lsl #4 - bcc Loop1 -Lbignum: - @ For very big divisors, we must shift it a bit at a time, or - @ we will be in danger of overflowing. - cmp divisor, #0x80000000 - cmpcc divisor, dividend - movcc divisor, divisor, lsl #1 - movcc curbit, curbit, lsl #1 - bcc Lbignum -Loop3: - @ Test for possible subtractions, and note which bits - @ are done in the result. On the final pass, this may subtract - @ too much from the dividend, but the result will be ok, since the - @ "bit" will have been shifted out at the bottom. - cmp dividend, divisor - subcs dividend, dividend, divisor - orrcs result, result, curbit - cmp dividend, divisor, lsr #1 - subcs dividend, dividend, divisor, lsr #1 - orrcs result, result, curbit, lsr #1 - cmp dividend, divisor, lsr #2 - subcs dividend, dividend, divisor, lsr #2 - orrcs result, result, curbit, lsr #2 - cmp dividend, divisor, lsr #3 - subcs dividend, dividend, divisor, lsr #3 - orrcs result, result, curbit, lsr #3 - cmp dividend, #0 @ Early termination? - movnes curbit, curbit, lsr #4 @ No, any more bits to do? - movne divisor, divisor, lsr #4 - bne Loop3 -Lgot_result: - mov r0, result - mov pc, lr -Ldiv0: - str lr, [sp, #-4]! - bl __div0 (PLT) - mov r0, #0 @ about as wrong as it could be - ldmia sp!, {pc} - .size __udivsi3 , . - __udivsi3 - -ENTRY(__aeabi_uidivmod) - - stmfd sp!, {r0, r1, ip, lr} - bl __aeabi_uidiv - ldmfd sp!, {r1, r2, ip, lr} - mul r3, r0, r2 - sub r1, r1, r3 - mov pc, lr -ENDPROC(__aeabi_uidivmod) - -ENTRY(__aeabi_idivmod) - - stmfd sp!, {r0, r1, ip, lr} - bl __aeabi_idiv - ldmfd sp!, {r1, r2, ip, lr} - mul r3, r0, r2 - sub r1, r1, r3 - mov pc, lr -ENDPROC(__aeabi_idivmod) diff --git a/arch/arm/lib/umodsi3.S b/arch/arm/lib/umodsi3.S deleted file mode 100644 index b166737..0000000 --- a/arch/arm/lib/umodsi3.S +++ /dev/null @@ -1,90 +0,0 @@ -#include <linux/linkage.h> - -/* # 1 "libgcc1.S" */ -@ libgcc1 routines for ARM cpu. -@ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk) -/* # 145 "libgcc1.S" */ -dividend .req r0 -divisor .req r1 -overdone .req r2 -curbit .req r3 -/* ip .req r12 */ -/* sp .req r13 */ -/* lr .req r14 */ -/* pc .req r15 */ - .text - .type __umodsi3 ,function - .align 0 - ENTRY(__umodsi3) - cmp divisor, #0 - beq Ldiv0 - mov curbit, #1 - cmp dividend, divisor - movcc pc, lr -Loop1: - @ Unless the divisor is very big, shift it up in multiples of - @ four bits, since this is the amount of unwinding in the main - @ division loop. Continue shifting until the divisor is - @ larger than the dividend. - cmp divisor, #0x10000000 - cmpcc divisor, dividend - movcc divisor, divisor, lsl #4 - movcc curbit, curbit, lsl #4 - bcc Loop1 -Lbignum: - @ For very big divisors, we must shift it a bit at a time, or - @ we will be in danger of overflowing. - cmp divisor, #0x80000000 - cmpcc divisor, dividend - movcc divisor, divisor, lsl #1 - movcc curbit, curbit, lsl #1 - bcc Lbignum -Loop3: - @ Test for possible subtractions. On the final pass, this may - @ subtract too much from the dividend, so keep track of which - @ subtractions are done, we can fix them up afterwards... - mov overdone, #0 - cmp dividend, divisor - subcs dividend, dividend, divisor - cmp dividend, divisor, lsr #1 - subcs dividend, dividend, divisor, lsr #1 - orrcs overdone, overdone, curbit, ror #1 - cmp dividend, divisor, lsr #2 - subcs dividend, dividend, divisor, lsr #2 - orrcs overdone, overdone, curbit, ror #2 - cmp dividend, divisor, lsr #3 - subcs dividend, dividend, divisor, lsr #3 - orrcs overdone, overdone, curbit, ror #3 - mov ip, curbit - cmp dividend, #0 @ Early termination? - movnes curbit, curbit, lsr #4 @ No, any more bits to do? - movne divisor, divisor, lsr #4 - bne Loop3 - @ Any subtractions that we should not have done will be recorded in - @ the top three bits of "overdone". Exactly which were not needed - @ are governed by the position of the bit, stored in ip. - @ If we terminated early, because dividend became zero, - @ then none of the below will match, since the bit in ip will not be - @ in the bottom nibble. - ands overdone, overdone, #0xe0000000 - moveq pc, lr @ No fixups needed - tst overdone, ip, ror #3 - addne dividend, dividend, divisor, lsr #3 - tst overdone, ip, ror #2 - addne dividend, dividend, divisor, lsr #2 - tst overdone, ip, ror #1 - addne dividend, dividend, divisor, lsr #1 - mov pc, lr -Ldiv0: - str lr, [sp, #-4]! - bl __div0 (PLT) - mov r0, #0 @ about as wrong as it could be - ldmia sp!, {pc} - .size __umodsi3 , . - __umodsi3 -/* # 320 "libgcc1.S" */ -/* # 421 "libgcc1.S" */ -/* # 433 "libgcc1.S" */ -/* # 456 "libgcc1.S" */ -/* # 500 "libgcc1.S" */ -/* # 580 "libgcc1.S" */ -ENDPROC(__umodsi3)