1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
215 lines
5.6 KiB
ArmAsm
215 lines
5.6 KiB
ArmAsm
/*
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* linux/arch/arm/vfp/vfphw.S
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*
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* Copyright (C) 2004 ARM Limited.
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* Written by Deep Blue Solutions Limited.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This code is called from the kernel's undefined instruction trap.
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* r9 holds the return address for successful handling.
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* lr holds the return address for unrecognised instructions.
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* r10 points at the start of the private FP workspace in the thread structure
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* sp points to a struct pt_regs (as defined in include/asm/proc/ptrace.h)
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*/
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#include <asm/thread_info.h>
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#include <asm/vfpmacros.h>
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#include "../kernel/entry-header.S"
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.macro DBGSTR, str
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#ifdef DEBUG
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stmfd sp!, {r0-r3, ip, lr}
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add r0, pc, #4
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bl printk
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b 1f
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.asciz "<7>VFP: \str\n"
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.balign 4
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1: ldmfd sp!, {r0-r3, ip, lr}
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#endif
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.endm
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.macro DBGSTR1, str, arg
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#ifdef DEBUG
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stmfd sp!, {r0-r3, ip, lr}
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mov r1, \arg
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add r0, pc, #4
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bl printk
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b 1f
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.asciz "<7>VFP: \str\n"
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.balign 4
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1: ldmfd sp!, {r0-r3, ip, lr}
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#endif
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.endm
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.macro DBGSTR3, str, arg1, arg2, arg3
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#ifdef DEBUG
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stmfd sp!, {r0-r3, ip, lr}
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mov r3, \arg3
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mov r2, \arg2
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mov r1, \arg1
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add r0, pc, #4
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bl printk
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b 1f
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.asciz "<7>VFP: \str\n"
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.balign 4
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1: ldmfd sp!, {r0-r3, ip, lr}
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#endif
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.endm
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@ VFP hardware support entry point.
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@
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@ r0 = faulted instruction
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@ r2 = faulted PC+4
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@ r9 = successful return
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@ r10 = vfp_state union
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@ lr = failure return
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.globl vfp_support_entry
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vfp_support_entry:
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DBGSTR3 "instr %08x pc %08x state %p", r0, r2, r10
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VFPFMRX r1, FPEXC @ Is the VFP enabled?
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DBGSTR1 "fpexc %08x", r1
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tst r1, #FPEXC_ENABLE
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bne look_for_VFP_exceptions @ VFP is already enabled
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DBGSTR1 "enable %x", r10
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ldr r3, last_VFP_context_address
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orr r1, r1, #FPEXC_ENABLE @ user FPEXC has the enable bit set
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ldr r4, [r3] @ last_VFP_context pointer
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bic r5, r1, #FPEXC_EXCEPTION @ make sure exceptions are disabled
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cmp r4, r10
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beq check_for_exception @ we are returning to the same
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@ process, so the registers are
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@ still there. In this case, we do
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@ not want to drop a pending exception.
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VFPFMXR FPEXC, r5 @ enable VFP, disable any pending
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@ exceptions, so we can get at the
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@ rest of it
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@ Save out the current registers to the old thread state
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DBGSTR1 "save old state %p", r4
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cmp r4, #0
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beq no_old_VFP_process
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VFPFMRX r5, FPSCR @ current status
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VFPFMRX r6, FPINST @ FPINST (always there, rev0 onwards)
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tst r1, #FPEXC_FPV2 @ is there an FPINST2 to read?
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VFPFMRX r8, FPINST2, NE @ FPINST2 if needed - avoids reading
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@ nonexistant reg on rev0
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VFPFSTMIA r4 @ save the working registers
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add r4, r4, #8*16+4
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stmia r4, {r1, r5, r6, r8} @ save FPEXC, FPSCR, FPINST, FPINST2
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@ and point r4 at the word at the
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@ start of the register dump
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no_old_VFP_process:
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DBGSTR1 "load state %p", r10
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str r10, [r3] @ update the last_VFP_context pointer
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@ Load the saved state back into the VFP
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add r4, r10, #8*16+4
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ldmia r4, {r1, r5, r6, r8} @ load FPEXC, FPSCR, FPINST, FPINST2
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VFPFLDMIA r10 @ reload the working registers while
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@ FPEXC is in a safe state
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tst r1, #FPEXC_FPV2 @ is there an FPINST2 to write?
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VFPFMXR FPINST2, r8, NE @ FPINST2 if needed - avoids writing
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@ nonexistant reg on rev0
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VFPFMXR FPINST, r6
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VFPFMXR FPSCR, r5 @ restore status
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check_for_exception:
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tst r1, #FPEXC_EXCEPTION
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bne process_exception @ might as well handle the pending
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@ exception before retrying branch
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@ out before setting an FPEXC that
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@ stops us reading stuff
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VFPFMXR FPEXC, r1 @ restore FPEXC last
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sub r2, r2, #4
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str r2, [sp, #S_PC] @ retry the instruction
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mov pc, r9 @ we think we have handled things
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look_for_VFP_exceptions:
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tst r1, #FPEXC_EXCEPTION
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bne process_exception
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VFPFMRX r5, FPSCR
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tst r5, #FPSCR_IXE @ IXE doesn't set FPEXC_EXCEPTION !
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bne process_exception
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@ Fall into hand on to next handler - appropriate coproc instr
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@ not recognised by VFP
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DBGSTR "not VFP"
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mov pc, lr
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process_exception:
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DBGSTR "bounce"
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sub r2, r2, #4
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str r2, [sp, #S_PC] @ retry the instruction on exit from
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@ the imprecise exception handling in
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@ the support code
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mov r2, sp @ nothing stacked - regdump is at TOS
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mov lr, r9 @ setup for a return to the user code.
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@ Now call the C code to package up the bounce to the support code
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@ r0 holds the trigger instruction
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@ r1 holds the FPEXC value
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@ r2 pointer to register dump
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b VFP9_bounce @ we have handled this - the support
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@ code will raise an exception if
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@ required. If not, the user code will
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@ retry the faulted instruction
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last_VFP_context_address:
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.word last_VFP_context
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.globl vfp_get_float
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vfp_get_float:
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add pc, pc, r0, lsl #3
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mov r0, r0
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.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
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mrc p10, 0, r0, c\dr, c0, 0 @ fmrs r0, s0
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mov pc, lr
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mrc p10, 0, r0, c\dr, c0, 4 @ fmrs r0, s1
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mov pc, lr
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.endr
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.globl vfp_put_float
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vfp_put_float:
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add pc, pc, r0, lsl #3
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mov r0, r0
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.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
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mcr p10, 0, r1, c\dr, c0, 0 @ fmsr r0, s0
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mov pc, lr
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mcr p10, 0, r1, c\dr, c0, 4 @ fmsr r0, s1
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mov pc, lr
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.endr
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.globl vfp_get_double
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vfp_get_double:
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mov r0, r0, lsr #1
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add pc, pc, r0, lsl #3
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mov r0, r0
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.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
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mrrc p10, 1, r0, r1, c\dr @ fmrrd r0, r1, d\dr
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mov pc, lr
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.endr
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@ virtual register 16 for compare with zero
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mov r0, #0
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mov r1, #0
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mov pc, lr
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.globl vfp_put_double
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vfp_put_double:
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mov r0, r0, lsr #1
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add pc, pc, r0, lsl #3
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mov r0, r0
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.irp dr,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15
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mcrr p10, 1, r1, r2, c\dr @ fmrrd r1, r2, d\dr
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mov pc, lr
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.endr
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