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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* O32 interface for the 64 (or N32) ABI.
*
* Copyright (C) 2002, 2014 Maciej W. Rozycki
*/
#include <asm/asm.h>
#include <asm/regdef.h>
/* O32 register size. */
#define O32_SZREG 4
/* Maximum number of arguments supported. Must be even! */
#define O32_ARGC 32
/* Number of static registers we save. */
#define O32_STATC 11
/* Argument area frame size. */
#define O32_ARGSZ (O32_SZREG * O32_ARGC)
/* Static register save area frame size. */
#define O32_STATSZ (SZREG * O32_STATC)
/* Stack pointer register save area frame size. */
#define O32_SPSZ SZREG
/* Combined area frame size. */
#define O32_FRAMESZ (O32_ARGSZ + O32_SPSZ + O32_STATSZ)
/* Switched stack frame size. */
#define O32_NFRAMESZ (O32_ARGSZ + O32_SPSZ)
.text
/*
* O32 function call dispatcher, for interfacing 32-bit ROM routines.
*
* The standard 64 (N32) calling sequence is supported, with a0 holding
* a function pointer, a1 a pointer to the new stack to call the
* function with or 0 if no stack switching is requested, a2-a7 -- the
* function call's first six arguments, and the stack -- the remaining
* arguments (up to O32_ARGC, including a2-a7). Static registers, gp
* and fp are preserved, v0 holds the result. This code relies on the
* called o32 function for sp and ra restoration and this dispatcher has
* to be placed in a KSEGx (or KUSEG) address space. Any pointers
* passed have to point to addresses within one of these spaces as well.
*/
NESTED(call_o32, O32_FRAMESZ, ra)
REG_SUBU sp,O32_FRAMESZ
REG_S ra,O32_FRAMESZ-1*SZREG(sp)
REG_S fp,O32_FRAMESZ-2*SZREG(sp)
REG_S gp,O32_FRAMESZ-3*SZREG(sp)
REG_S s7,O32_FRAMESZ-4*SZREG(sp)
REG_S s6,O32_FRAMESZ-5*SZREG(sp)
REG_S s5,O32_FRAMESZ-6*SZREG(sp)
REG_S s4,O32_FRAMESZ-7*SZREG(sp)
REG_S s3,O32_FRAMESZ-8*SZREG(sp)
REG_S s2,O32_FRAMESZ-9*SZREG(sp)
REG_S s1,O32_FRAMESZ-10*SZREG(sp)
REG_S s0,O32_FRAMESZ-11*SZREG(sp)
move jp,a0
move fp,sp
beqz a1,0f
REG_SUBU fp,a1,O32_NFRAMESZ
0:
REG_S sp,O32_NFRAMESZ-1*SZREG(fp)
sll a0,a2,zero
sll a1,a3,zero
sll a2,a4,zero
sll a3,a5,zero
sw a6,4*O32_SZREG(fp)
sw a7,5*O32_SZREG(fp)
PTR_LA t0,O32_FRAMESZ(sp)
PTR_LA t1,6*O32_SZREG(fp)
li t2,O32_ARGC-6
1:
lw t3,(t0)
REG_ADDU t0,SZREG
sw t3,(t1)
REG_SUBU t2,1
REG_ADDU t1,O32_SZREG
bnez t2,1b
move sp,fp
jalr jp
REG_L sp,O32_NFRAMESZ-1*SZREG(sp)
REG_L s0,O32_FRAMESZ-11*SZREG(sp)
REG_L s1,O32_FRAMESZ-10*SZREG(sp)
REG_L s2,O32_FRAMESZ-9*SZREG(sp)
REG_L s3,O32_FRAMESZ-8*SZREG(sp)
REG_L s4,O32_FRAMESZ-7*SZREG(sp)
REG_L s5,O32_FRAMESZ-6*SZREG(sp)
REG_L s6,O32_FRAMESZ-5*SZREG(sp)
REG_L s7,O32_FRAMESZ-4*SZREG(sp)
REG_L gp,O32_FRAMESZ-3*SZREG(sp)
REG_L fp,O32_FRAMESZ-2*SZREG(sp)
REG_L ra,O32_FRAMESZ-1*SZREG(sp)
REG_ADDU sp,O32_FRAMESZ
jr ra
END(call_o32)
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