240 lines
5.7 KiB
C
240 lines
5.7 KiB
C
/*
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* muldiv.c: Hardware multiply/division illegal instruction trap
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* for sun4c/sun4 (which do not have those instructions)
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*
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* Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
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* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
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*
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* 2004-12-25 Krzysztof Helt (krzysztof.h1@wp.pl)
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* - fixed registers constrains in inline assembly declarations
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <asm/ptrace.h>
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#include <asm/processor.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include "kernel.h"
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/* #define DEBUG_MULDIV */
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static inline int has_imm13(int insn)
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{
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return (insn & 0x2000);
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}
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static inline int is_foocc(int insn)
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{
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return (insn & 0x800000);
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}
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static inline int sign_extend_imm13(int imm)
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{
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return imm << 19 >> 19;
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}
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static inline void advance(struct pt_regs *regs)
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{
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regs->pc = regs->npc;
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regs->npc += 4;
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}
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static inline void maybe_flush_windows(unsigned int rs1, unsigned int rs2,
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unsigned int rd)
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{
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if(rs2 >= 16 || rs1 >= 16 || rd >= 16) {
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/* Wheee... */
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__asm__ __volatile__("save %sp, -0x40, %sp\n\t"
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"save %sp, -0x40, %sp\n\t"
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"save %sp, -0x40, %sp\n\t"
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"save %sp, -0x40, %sp\n\t"
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"save %sp, -0x40, %sp\n\t"
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"save %sp, -0x40, %sp\n\t"
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"save %sp, -0x40, %sp\n\t"
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"restore; restore; restore; restore;\n\t"
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"restore; restore; restore;\n\t");
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}
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}
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#define fetch_reg(reg, regs) ({ \
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struct reg_window32 __user *win; \
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register unsigned long ret; \
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\
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if (!(reg)) ret = 0; \
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else if ((reg) < 16) { \
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ret = regs->u_regs[(reg)]; \
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} else { \
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/* Ho hum, the slightly complicated case. */ \
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win = (struct reg_window32 __user *)regs->u_regs[UREG_FP];\
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if (get_user (ret, &win->locals[(reg) - 16])) return -1;\
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} \
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ret; \
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})
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static inline int
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store_reg(unsigned int result, unsigned int reg, struct pt_regs *regs)
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{
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struct reg_window32 __user *win;
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if (!reg)
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return 0;
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if (reg < 16) {
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regs->u_regs[reg] = result;
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return 0;
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} else {
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/* need to use put_user() in this case: */
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win = (struct reg_window32 __user *) regs->u_regs[UREG_FP];
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return (put_user(result, &win->locals[reg - 16]));
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}
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}
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/* Should return 0 if mul/div emulation succeeded and SIGILL should
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* not be issued.
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*/
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int do_user_muldiv(struct pt_regs *regs, unsigned long pc)
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{
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unsigned int insn;
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int inst;
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unsigned int rs1, rs2, rdv;
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if (!pc)
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return -1; /* This happens to often, I think */
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if (get_user (insn, (unsigned int __user *)pc))
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return -1;
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if ((insn & 0xc1400000) != 0x80400000)
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return -1;
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inst = ((insn >> 19) & 0xf);
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if ((inst & 0xe) != 10 && (inst & 0xe) != 14)
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return -1;
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/* Now we know we have to do something with umul, smul, udiv or sdiv */
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rs1 = (insn >> 14) & 0x1f;
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rs2 = insn & 0x1f;
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rdv = (insn >> 25) & 0x1f;
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if (has_imm13(insn)) {
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maybe_flush_windows(rs1, 0, rdv);
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rs2 = sign_extend_imm13(insn);
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} else {
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maybe_flush_windows(rs1, rs2, rdv);
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rs2 = fetch_reg(rs2, regs);
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}
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rs1 = fetch_reg(rs1, regs);
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switch (inst) {
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case 10: /* umul */
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#ifdef DEBUG_MULDIV
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printk ("unsigned muldiv: 0x%x * 0x%x = ", rs1, rs2);
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#endif
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__asm__ __volatile__ ("\n\t"
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"mov %0, %%o0\n\t"
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"call .umul\n\t"
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" mov %1, %%o1\n\t"
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"mov %%o0, %0\n\t"
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"mov %%o1, %1\n\t"
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: "=r" (rs1), "=r" (rs2)
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: "0" (rs1), "1" (rs2)
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: "o0", "o1", "o2", "o3", "o4", "o5", "o7", "cc");
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#ifdef DEBUG_MULDIV
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printk ("0x%x%08x\n", rs2, rs1);
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#endif
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if (store_reg(rs1, rdv, regs))
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return -1;
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regs->y = rs2;
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break;
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case 11: /* smul */
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#ifdef DEBUG_MULDIV
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printk ("signed muldiv: 0x%x * 0x%x = ", rs1, rs2);
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#endif
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__asm__ __volatile__ ("\n\t"
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"mov %0, %%o0\n\t"
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"call .mul\n\t"
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" mov %1, %%o1\n\t"
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"mov %%o0, %0\n\t"
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"mov %%o1, %1\n\t"
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: "=r" (rs1), "=r" (rs2)
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: "0" (rs1), "1" (rs2)
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: "o0", "o1", "o2", "o3", "o4", "o5", "o7", "cc");
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#ifdef DEBUG_MULDIV
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printk ("0x%x%08x\n", rs2, rs1);
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#endif
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if (store_reg(rs1, rdv, regs))
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return -1;
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regs->y = rs2;
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break;
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case 14: /* udiv */
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#ifdef DEBUG_MULDIV
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printk ("unsigned muldiv: 0x%x%08x / 0x%x = ", regs->y, rs1, rs2);
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#endif
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if (!rs2) {
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#ifdef DEBUG_MULDIV
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printk ("DIVISION BY ZERO\n");
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#endif
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handle_hw_divzero (regs, pc, regs->npc, regs->psr);
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return 0;
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}
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__asm__ __volatile__ ("\n\t"
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"mov %2, %%o0\n\t"
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"mov %0, %%o1\n\t"
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"mov %%g0, %%o2\n\t"
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"call __udivdi3\n\t"
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" mov %1, %%o3\n\t"
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"mov %%o1, %0\n\t"
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"mov %%o0, %1\n\t"
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: "=r" (rs1), "=r" (rs2)
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: "r" (regs->y), "0" (rs1), "1" (rs2)
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: "o0", "o1", "o2", "o3", "o4", "o5", "o7",
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"g1", "g2", "g3", "cc");
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#ifdef DEBUG_MULDIV
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printk ("0x%x\n", rs1);
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#endif
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if (store_reg(rs1, rdv, regs))
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return -1;
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break;
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case 15: /* sdiv */
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#ifdef DEBUG_MULDIV
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printk ("signed muldiv: 0x%x%08x / 0x%x = ", regs->y, rs1, rs2);
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#endif
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if (!rs2) {
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#ifdef DEBUG_MULDIV
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printk ("DIVISION BY ZERO\n");
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#endif
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handle_hw_divzero (regs, pc, regs->npc, regs->psr);
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return 0;
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}
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__asm__ __volatile__ ("\n\t"
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"mov %2, %%o0\n\t"
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"mov %0, %%o1\n\t"
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"mov %%g0, %%o2\n\t"
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"call __divdi3\n\t"
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" mov %1, %%o3\n\t"
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"mov %%o1, %0\n\t"
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"mov %%o0, %1\n\t"
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: "=r" (rs1), "=r" (rs2)
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: "r" (regs->y), "0" (rs1), "1" (rs2)
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: "o0", "o1", "o2", "o3", "o4", "o5", "o7",
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"g1", "g2", "g3", "cc");
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#ifdef DEBUG_MULDIV
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printk ("0x%x\n", rs1);
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#endif
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if (store_reg(rs1, rdv, regs))
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return -1;
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break;
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}
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if (is_foocc (insn)) {
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regs->psr &= ~PSR_ICC;
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if ((inst & 0xe) == 14) {
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/* ?div */
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if (rs2) regs->psr |= PSR_V;
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}
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if (!rs1) regs->psr |= PSR_Z;
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if (((int)rs1) < 0) regs->psr |= PSR_N;
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#ifdef DEBUG_MULDIV
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printk ("psr muldiv: %08x\n", regs->psr);
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#endif
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}
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advance(regs);
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return 0;
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}
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