/*
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* O32 interface for the 64 (or N32) ABI.
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*
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* Copyright (C) 2002, 2014 Maciej W. Rozycki
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <asm/asm.h>
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#include <asm/regdef.h>
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/* O32 register size. */
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#define O32_SZREG 4
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/* Maximum number of arguments supported. Must be even! */
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#define O32_ARGC 32
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/* Number of static registers we save. */
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#define O32_STATC 11
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/* Argument area frame size. */
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#define O32_ARGSZ (O32_SZREG * O32_ARGC)
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/* Static register save area frame size. */
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#define O32_STATSZ (SZREG * O32_STATC)
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/* Stack pointer register save area frame size. */
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#define O32_SPSZ SZREG
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/* Combined area frame size. */
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#define O32_FRAMESZ (O32_ARGSZ + O32_SPSZ + O32_STATSZ)
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/* Switched stack frame size. */
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#define O32_NFRAMESZ (O32_ARGSZ + O32_SPSZ)
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.text
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/*
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* O32 function call dispatcher, for interfacing 32-bit ROM routines.
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*
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* The standard 64 (N32) calling sequence is supported, with a0 holding
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* a function pointer, a1 a pointer to the new stack to call the
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* function with or 0 if no stack switching is requested, a2-a7 -- the
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* function call's first six arguments, and the stack -- the remaining
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* arguments (up to O32_ARGC, including a2-a7). Static registers, gp
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* and fp are preserved, v0 holds the result. This code relies on the
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* called o32 function for sp and ra restoration and this dispatcher has
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* to be placed in a KSEGx (or KUSEG) address space. Any pointers
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* passed have to point to addresses within one of these spaces as well.
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*/
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NESTED(call_o32, O32_FRAMESZ, ra)
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REG_SUBU sp,O32_FRAMESZ
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REG_S ra,O32_FRAMESZ-1*SZREG(sp)
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REG_S fp,O32_FRAMESZ-2*SZREG(sp)
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REG_S gp,O32_FRAMESZ-3*SZREG(sp)
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REG_S s7,O32_FRAMESZ-4*SZREG(sp)
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REG_S s6,O32_FRAMESZ-5*SZREG(sp)
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REG_S s5,O32_FRAMESZ-6*SZREG(sp)
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REG_S s4,O32_FRAMESZ-7*SZREG(sp)
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REG_S s3,O32_FRAMESZ-8*SZREG(sp)
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REG_S s2,O32_FRAMESZ-9*SZREG(sp)
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REG_S s1,O32_FRAMESZ-10*SZREG(sp)
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REG_S s0,O32_FRAMESZ-11*SZREG(sp)
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move jp,a0
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move fp,sp
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beqz a1,0f
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REG_SUBU fp,a1,O32_NFRAMESZ
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0:
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REG_S sp,O32_NFRAMESZ-1*SZREG(fp)
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sll a0,a2,zero
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sll a1,a3,zero
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sll a2,a4,zero
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sll a3,a5,zero
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sw a6,4*O32_SZREG(fp)
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sw a7,5*O32_SZREG(fp)
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PTR_LA t0,O32_FRAMESZ(sp)
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PTR_LA t1,6*O32_SZREG(fp)
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li t2,O32_ARGC-6
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1:
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lw t3,(t0)
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REG_ADDU t0,SZREG
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sw t3,(t1)
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REG_SUBU t2,1
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REG_ADDU t1,O32_SZREG
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bnez t2,1b
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move sp,fp
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jalr jp
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REG_L sp,O32_NFRAMESZ-1*SZREG(sp)
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REG_L s0,O32_FRAMESZ-11*SZREG(sp)
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REG_L s1,O32_FRAMESZ-10*SZREG(sp)
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REG_L s2,O32_FRAMESZ-9*SZREG(sp)
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REG_L s3,O32_FRAMESZ-8*SZREG(sp)
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REG_L s4,O32_FRAMESZ-7*SZREG(sp)
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REG_L s5,O32_FRAMESZ-6*SZREG(sp)
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REG_L s6,O32_FRAMESZ-5*SZREG(sp)
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REG_L s7,O32_FRAMESZ-4*SZREG(sp)
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REG_L gp,O32_FRAMESZ-3*SZREG(sp)
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REG_L fp,O32_FRAMESZ-2*SZREG(sp)
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REG_L ra,O32_FRAMESZ-1*SZREG(sp)
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REG_ADDU sp,O32_FRAMESZ
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jr ra
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END(call_o32)
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