summaryrefslogtreecommitdiffstats
path: root/arch/mips/math-emu/cp1emu.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/math-emu/cp1emu.c')
-rw-r--r--arch/mips/math-emu/cp1emu.c1322
1 files changed, 1322 insertions, 0 deletions
diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
new file mode 100644
index 00000000000..20a552be02e
--- /dev/null
+++ b/arch/mips/math-emu/cp1emu.c
@@ -0,0 +1,1322 @@
+/*
+ * cp1emu.c: a MIPS coprocessor 1 (fpu) instruction emulator
+ *
+ * MIPS floating point support
+ * Copyright (C) 1994-2000 Algorithmics Ltd.
+ * http://www.algor.co.uk
+ *
+ * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
+ * Copyright (C) 2000 MIPS Technologies, Inc.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * A complete emulator for MIPS coprocessor 1 instructions. This is
+ * required for #float(switch) or #float(trap), where it catches all
+ * COP1 instructions via the "CoProcessor Unusable" exception.
+ *
+ * More surprisingly it is also required for #float(ieee), to help out
+ * the hardware fpu at the boundaries of the IEEE-754 representation
+ * (denormalised values, infinities, underflow, etc). It is made
+ * quite nasty because emulation of some non-COP1 instructions is
+ * required, e.g. in branch delay slots.
+ *
+ * Note if you know that you won't have an fpu, then you'll get much
+ * better performance by compiling with -msoft-float!
+ */
+#include <linux/sched.h>
+
+#include <asm/inst.h>
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/signal.h>
+#include <asm/mipsregs.h>
+#include <asm/fpu_emulator.h>
+#include <asm/uaccess.h>
+#include <asm/branch.h>
+
+#include "ieee754.h"
+#include "dsemul.h"
+
+/* Strap kernel emulator for full MIPS IV emulation */
+
+#ifdef __mips
+#undef __mips
+#endif
+#define __mips 4
+
+/* Function which emulates a floating point instruction. */
+
+static int fpu_emu(struct pt_regs *, struct mips_fpu_soft_struct *,
+ mips_instruction);
+
+#if __mips >= 4 && __mips != 32
+static int fpux_emu(struct pt_regs *,
+ struct mips_fpu_soft_struct *, mips_instruction);
+#endif
+
+/* Further private data for which no space exists in mips_fpu_soft_struct */
+
+struct mips_fpu_emulator_private fpuemuprivate;
+
+/* Control registers */
+
+#define FPCREG_RID 0 /* $0 = revision id */
+#define FPCREG_CSR 31 /* $31 = csr */
+
+/* Convert Mips rounding mode (0..3) to IEEE library modes. */
+static const unsigned char ieee_rm[4] = {
+ IEEE754_RN, IEEE754_RZ, IEEE754_RU, IEEE754_RD
+};
+
+#if __mips >= 4
+/* convert condition code register number to csr bit */
+static const unsigned int fpucondbit[8] = {
+ FPU_CSR_COND0,
+ FPU_CSR_COND1,
+ FPU_CSR_COND2,
+ FPU_CSR_COND3,
+ FPU_CSR_COND4,
+ FPU_CSR_COND5,
+ FPU_CSR_COND6,
+ FPU_CSR_COND7
+};
+#endif
+
+
+/*
+ * Redundant with logic already in kernel/branch.c,
+ * embedded in compute_return_epc. At some point,
+ * a single subroutine should be used across both
+ * modules.
+ */
+static int isBranchInstr(mips_instruction * i)
+{
+ switch (MIPSInst_OPCODE(*i)) {
+ case spec_op:
+ switch (MIPSInst_FUNC(*i)) {
+ case jalr_op:
+ case jr_op:
+ return 1;
+ }
+ break;
+
+ case bcond_op:
+ switch (MIPSInst_RT(*i)) {
+ case bltz_op:
+ case bgez_op:
+ case bltzl_op:
+ case bgezl_op:
+ case bltzal_op:
+ case bgezal_op:
+ case bltzall_op:
+ case bgezall_op:
+ return 1;
+ }
+ break;
+
+ case j_op:
+ case jal_op:
+ case jalx_op:
+ case beq_op:
+ case bne_op:
+ case blez_op:
+ case bgtz_op:
+ case beql_op:
+ case bnel_op:
+ case blezl_op:
+ case bgtzl_op:
+ return 1;
+
+ case cop0_op:
+ case cop1_op:
+ case cop2_op:
+ case cop1x_op:
+ if (MIPSInst_RS(*i) == bc_op)
+ return 1;
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * In the Linux kernel, we support selection of FPR format on the
+ * basis of the Status.FR bit. This does imply that, if a full 32
+ * FPRs are desired, there needs to be a flip-flop that can be written
+ * to one at that bit position. In any case, O32 MIPS ABI uses
+ * only the even FPRs (Status.FR = 0).
+ */
+
+#define CP0_STATUS_FR_SUPPORT
+
+#ifdef CP0_STATUS_FR_SUPPORT
+#define FR_BIT ST0_FR
+#else
+#define FR_BIT 0
+#endif
+
+#define SIFROMREG(si,x) ((si) = \
+ (xcp->cp0_status & FR_BIT) || !(x & 1) ? \
+ (int)ctx->fpr[x] : \
+ (int)(ctx->fpr[x & ~1] >> 32 ))
+#define SITOREG(si,x) (ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] = \
+ (xcp->cp0_status & FR_BIT) || !(x & 1) ? \
+ ctx->fpr[x & ~1] >> 32 << 32 | (u32)(si) : \
+ ctx->fpr[x & ~1] << 32 >> 32 | (u64)(si) << 32)
+
+#define DIFROMREG(di,x) ((di) = \
+ ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)])
+#define DITOREG(di,x) (ctx->fpr[x & ~((xcp->cp0_status & FR_BIT) == 0)] \
+ = (di))
+
+#define SPFROMREG(sp,x) SIFROMREG((sp).bits,x)
+#define SPTOREG(sp,x) SITOREG((sp).bits,x)
+#define DPFROMREG(dp,x) DIFROMREG((dp).bits,x)
+#define DPTOREG(dp,x) DITOREG((dp).bits,x)
+
+/*
+ * Emulate the single floating point instruction pointed at by EPC.
+ * Two instructions if the instruction is in a branch delay slot.
+ */
+
+static int cop1Emulate(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx)
+{
+ mips_instruction ir;
+ vaddr_t emulpc, contpc;
+ unsigned int cond;
+
+ if (get_user(ir, (mips_instruction *) xcp->cp0_epc)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+
+ /* XXX NEC Vr54xx bug workaround */
+ if ((xcp->cp0_cause & CAUSEF_BD) && !isBranchInstr(&ir))
+ xcp->cp0_cause &= ~CAUSEF_BD;
+
+ if (xcp->cp0_cause & CAUSEF_BD) {
+ /*
+ * The instruction to be emulated is in a branch delay slot
+ * which means that we have to emulate the branch instruction
+ * BEFORE we do the cop1 instruction.
+ *
+ * This branch could be a COP1 branch, but in that case we
+ * would have had a trap for that instruction, and would not
+ * come through this route.
+ *
+ * Linux MIPS branch emulator operates on context, updating the
+ * cp0_epc.
+ */
+ emulpc = REG_TO_VA(xcp->cp0_epc + 4); /* Snapshot emulation target */
+
+ if (__compute_return_epc(xcp)) {
+#ifdef CP1DBG
+ printk("failed to emulate branch at %p\n",
+ REG_TO_VA(xcp->cp0_epc));
+#endif
+ return SIGILL;
+ }
+ if (get_user(ir, (mips_instruction *) emulpc)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ /* __compute_return_epc() will have updated cp0_epc */
+ contpc = REG_TO_VA xcp->cp0_epc;
+ /* In order not to confuse ptrace() et al, tweak context */
+ xcp->cp0_epc = VA_TO_REG emulpc - 4;
+ }
+ else {
+ emulpc = REG_TO_VA xcp->cp0_epc;
+ contpc = REG_TO_VA(xcp->cp0_epc + 4);
+ }
+
+ emul:
+ fpuemuprivate.stats.emulated++;
+ switch (MIPSInst_OPCODE(ir)) {
+#ifndef SINGLE_ONLY_FPU
+ case ldc1_op:{
+ u64 *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)] +
+ MIPSInst_SIMM(ir));
+ u64 val;
+
+ fpuemuprivate.stats.loads++;
+ if (get_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ DITOREG(val, MIPSInst_RT(ir));
+ break;
+ }
+
+ case sdc1_op:{
+ u64 *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)] +
+ MIPSInst_SIMM(ir));
+ u64 val;
+
+ fpuemuprivate.stats.stores++;
+ DIFROMREG(val, MIPSInst_RT(ir));
+ if (put_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ break;
+ }
+#endif
+
+ case lwc1_op:{
+ u32 *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)] +
+ MIPSInst_SIMM(ir));
+ u32 val;
+
+ fpuemuprivate.stats.loads++;
+ if (get_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+#ifdef SINGLE_ONLY_FPU
+ if (MIPSInst_RT(ir) & 1) {
+ /* illegal register in single-float mode */
+ return SIGILL;
+ }
+#endif
+ SITOREG(val, MIPSInst_RT(ir));
+ break;
+ }
+
+ case swc1_op:{
+ u32 *va = REG_TO_VA(xcp->regs[MIPSInst_RS(ir)] +
+ MIPSInst_SIMM(ir));
+ u32 val;
+
+ fpuemuprivate.stats.stores++;
+#ifdef SINGLE_ONLY_FPU
+ if (MIPSInst_RT(ir) & 1) {
+ /* illegal register in single-float mode */
+ return SIGILL;
+ }
+#endif
+ SIFROMREG(val, MIPSInst_RT(ir));
+ if (put_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ break;
+ }
+
+ case cop1_op:
+ switch (MIPSInst_RS(ir)) {
+
+#if __mips64 && !defined(SINGLE_ONLY_FPU)
+ case dmfc_op:
+ /* copregister fs -> gpr[rt] */
+ if (MIPSInst_RT(ir) != 0) {
+ DIFROMREG(xcp->regs[MIPSInst_RT(ir)],
+ MIPSInst_RD(ir));
+ }
+ break;
+
+ case dmtc_op:
+ /* copregister fs <- rt */
+ DITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
+ break;
+#endif
+
+ case mfc_op:
+ /* copregister rd -> gpr[rt] */
+#ifdef SINGLE_ONLY_FPU
+ if (MIPSInst_RD(ir) & 1) {
+ /* illegal register in single-float mode */
+ return SIGILL;
+ }
+#endif
+ if (MIPSInst_RT(ir) != 0) {
+ SIFROMREG(xcp->regs[MIPSInst_RT(ir)],
+ MIPSInst_RD(ir));
+ }
+ break;
+
+ case mtc_op:
+ /* copregister rd <- rt */
+#ifdef SINGLE_ONLY_FPU
+ if (MIPSInst_RD(ir) & 1) {
+ /* illegal register in single-float mode */
+ return SIGILL;
+ }
+#endif
+ SITOREG(xcp->regs[MIPSInst_RT(ir)], MIPSInst_RD(ir));
+ break;
+
+ case cfc_op:{
+ /* cop control register rd -> gpr[rt] */
+ u32 value;
+
+ if (ir == CP1UNDEF) {
+ return do_dsemulret(xcp);
+ }
+ if (MIPSInst_RD(ir) == FPCREG_CSR) {
+ value = ctx->fcr31;
+#ifdef CSRTRACE
+ printk("%p gpr[%d]<-csr=%08x\n",
+ REG_TO_VA(xcp->cp0_epc),
+ MIPSInst_RT(ir), value);
+#endif
+ }
+ else if (MIPSInst_RD(ir) == FPCREG_RID)
+ value = 0;
+ else
+ value = 0;
+ if (MIPSInst_RT(ir))
+ xcp->regs[MIPSInst_RT(ir)] = value;
+ break;
+ }
+
+ case ctc_op:{
+ /* copregister rd <- rt */
+ u32 value;
+
+ if (MIPSInst_RT(ir) == 0)
+ value = 0;
+ else
+ value = xcp->regs[MIPSInst_RT(ir)];
+
+ /* we only have one writable control reg
+ */
+ if (MIPSInst_RD(ir) == FPCREG_CSR) {
+#ifdef CSRTRACE
+ printk("%p gpr[%d]->csr=%08x\n",
+ REG_TO_VA(xcp->cp0_epc),
+ MIPSInst_RT(ir), value);
+#endif
+ ctx->fcr31 = value;
+ /* copy new rounding mode and
+ flush bit to ieee library state! */
+ ieee754_csr.nod = (ctx->fcr31 & 0x1000000) != 0;
+ ieee754_csr.rm = ieee_rm[value & 0x3];
+ }
+ if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
+ return SIGFPE;
+ }
+ break;
+ }
+
+ case bc_op:{
+ int likely = 0;
+
+ if (xcp->cp0_cause & CAUSEF_BD)
+ return SIGILL;
+
+#if __mips >= 4
+ cond = ctx->fcr31 & fpucondbit[MIPSInst_RT(ir) >> 2];
+#else
+ cond = ctx->fcr31 & FPU_CSR_COND;
+#endif
+ switch (MIPSInst_RT(ir) & 3) {
+ case bcfl_op:
+ likely = 1;
+ case bcf_op:
+ cond = !cond;
+ break;
+ case bctl_op:
+ likely = 1;
+ case bct_op:
+ break;
+ default:
+ /* thats an illegal instruction */
+ return SIGILL;
+ }
+
+ xcp->cp0_cause |= CAUSEF_BD;
+ if (cond) {
+ /* branch taken: emulate dslot
+ * instruction
+ */
+ xcp->cp0_epc += 4;
+ contpc = REG_TO_VA
+ (xcp->cp0_epc +
+ (MIPSInst_SIMM(ir) << 2));
+
+ if (get_user(ir, (mips_instruction *)
+ REG_TO_VA xcp->cp0_epc)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+
+ switch (MIPSInst_OPCODE(ir)) {
+ case lwc1_op:
+ case swc1_op:
+#if (__mips >= 2 || __mips64) && !defined(SINGLE_ONLY_FPU)
+ case ldc1_op:
+ case sdc1_op:
+#endif
+ case cop1_op:
+#if __mips >= 4 && __mips != 32
+ case cop1x_op:
+#endif
+ /* its one of ours */
+ goto emul;
+#if __mips >= 4
+ case spec_op:
+ if (MIPSInst_FUNC(ir) == movc_op)
+ goto emul;
+ break;
+#endif
+ }
+
+ /*
+ * Single step the non-cp1
+ * instruction in the dslot
+ */
+ return mips_dsemul(xcp, ir, VA_TO_REG contpc);
+ }
+ else {
+ /* branch not taken */
+ if (likely) {
+ /*
+ * branch likely nullifies
+ * dslot if not taken
+ */
+ xcp->cp0_epc += 4;
+ contpc += 4;
+ /*
+ * else continue & execute
+ * dslot as normal insn
+ */
+ }
+ }
+ break;
+ }
+
+ default:
+ if (!(MIPSInst_RS(ir) & 0x10))
+ return SIGILL;
+ {
+ int sig;
+
+ /* a real fpu computation instruction */
+ if ((sig = fpu_emu(xcp, ctx, ir)))
+ return sig;
+ }
+ }
+ break;
+
+#if __mips >= 4 && __mips != 32
+ case cop1x_op:{
+ int sig;
+
+ if ((sig = fpux_emu(xcp, ctx, ir)))
+ return sig;
+ break;
+ }
+#endif
+
+#if __mips >= 4
+ case spec_op:
+ if (MIPSInst_FUNC(ir) != movc_op)
+ return SIGILL;
+ cond = fpucondbit[MIPSInst_RT(ir) >> 2];
+ if (((ctx->fcr31 & cond) != 0) == ((MIPSInst_RT(ir) & 1) != 0))
+ xcp->regs[MIPSInst_RD(ir)] =
+ xcp->regs[MIPSInst_RS(ir)];
+ break;
+#endif
+
+ default:
+ return SIGILL;
+ }
+
+ /* we did it !! */
+ xcp->cp0_epc = VA_TO_REG(contpc);
+ xcp->cp0_cause &= ~CAUSEF_BD;
+ return 0;
+}
+
+/*
+ * Conversion table from MIPS compare ops 48-63
+ * cond = ieee754dp_cmp(x,y,IEEE754_UN,sig);
+ */
+static const unsigned char cmptab[8] = {
+ 0, /* cmp_0 (sig) cmp_sf */
+ IEEE754_CUN, /* cmp_un (sig) cmp_ngle */
+ IEEE754_CEQ, /* cmp_eq (sig) cmp_seq */
+ IEEE754_CEQ | IEEE754_CUN, /* cmp_ueq (sig) cmp_ngl */
+ IEEE754_CLT, /* cmp_olt (sig) cmp_lt */
+ IEEE754_CLT | IEEE754_CUN, /* cmp_ult (sig) cmp_nge */
+ IEEE754_CLT | IEEE754_CEQ, /* cmp_ole (sig) cmp_le */
+ IEEE754_CLT | IEEE754_CEQ | IEEE754_CUN, /* cmp_ule (sig) cmp_ngt */
+};
+
+
+#if __mips >= 4 && __mips != 32
+
+/*
+ * Additional MIPS4 instructions
+ */
+
+#define DEF3OP(name, p, f1, f2, f3) \
+static ieee754##p fpemu_##p##_##name (ieee754##p r, ieee754##p s, \
+ ieee754##p t) \
+{ \
+ struct ieee754_csr ieee754_csr_save; \
+ s = f1 (s, t); \
+ ieee754_csr_save = ieee754_csr; \
+ s = f2 (s, r); \
+ ieee754_csr_save.cx |= ieee754_csr.cx; \
+ ieee754_csr_save.sx |= ieee754_csr.sx; \
+ s = f3 (s); \
+ ieee754_csr.cx |= ieee754_csr_save.cx; \
+ ieee754_csr.sx |= ieee754_csr_save.sx; \
+ return s; \
+}
+
+static ieee754dp fpemu_dp_recip(ieee754dp d)
+{
+ return ieee754dp_div(ieee754dp_one(0), d);
+}
+
+static ieee754dp fpemu_dp_rsqrt(ieee754dp d)
+{
+ return ieee754dp_div(ieee754dp_one(0), ieee754dp_sqrt(d));
+}
+
+static ieee754sp fpemu_sp_recip(ieee754sp s)
+{
+ return ieee754sp_div(ieee754sp_one(0), s);
+}
+
+static ieee754sp fpemu_sp_rsqrt(ieee754sp s)
+{
+ return ieee754sp_div(ieee754sp_one(0), ieee754sp_sqrt(s));
+}
+
+DEF3OP(madd, sp, ieee754sp_mul, ieee754sp_add,);
+DEF3OP(msub, sp, ieee754sp_mul, ieee754sp_sub,);
+DEF3OP(nmadd, sp, ieee754sp_mul, ieee754sp_add, ieee754sp_neg);
+DEF3OP(nmsub, sp, ieee754sp_mul, ieee754sp_sub, ieee754sp_neg);
+DEF3OP(madd, dp, ieee754dp_mul, ieee754dp_add,);
+DEF3OP(msub, dp, ieee754dp_mul, ieee754dp_sub,);
+DEF3OP(nmadd, dp, ieee754dp_mul, ieee754dp_add, ieee754dp_neg);
+DEF3OP(nmsub, dp, ieee754dp_mul, ieee754dp_sub, ieee754dp_neg);
+
+static int fpux_emu(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx,
+ mips_instruction ir)
+{
+ unsigned rcsr = 0; /* resulting csr */
+
+ fpuemuprivate.stats.cp1xops++;
+
+ switch (MIPSInst_FMA_FFMT(ir)) {
+ case s_fmt:{ /* 0 */
+
+ ieee754sp(*handler) (ieee754sp, ieee754sp, ieee754sp);
+ ieee754sp fd, fr, fs, ft;
+ u32 *va;
+ u32 val;
+
+ switch (MIPSInst_FUNC(ir)) {
+ case lwxc1_op:
+ va = REG_TO_VA(xcp->regs[MIPSInst_FR(ir)] +
+ xcp->regs[MIPSInst_FT(ir)]);
+
+ fpuemuprivate.stats.loads++;
+ if (get_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+#ifdef SINGLE_ONLY_FPU
+ if (MIPSInst_FD(ir) & 1) {
+ /* illegal register in single-float
+ * mode
+ */
+ return SIGILL;
+ }
+#endif
+ SITOREG(val, MIPSInst_FD(ir));
+ break;
+
+ case swxc1_op:
+ va = REG_TO_VA(xcp->regs[MIPSInst_FR(ir)] +
+ xcp->regs[MIPSInst_FT(ir)]);
+
+ fpuemuprivate.stats.stores++;
+#ifdef SINGLE_ONLY_FPU
+ if (MIPSInst_FS(ir) & 1) {
+ /* illegal register in single-float
+ * mode
+ */
+ return SIGILL;
+ }
+#endif
+
+ SIFROMREG(val, MIPSInst_FS(ir));
+ if (put_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ break;
+
+ case madd_s_op:
+ handler = fpemu_sp_madd;
+ goto scoptop;
+ case msub_s_op:
+ handler = fpemu_sp_msub;
+ goto scoptop;
+ case nmadd_s_op:
+ handler = fpemu_sp_nmadd;
+ goto scoptop;
+ case nmsub_s_op:
+ handler = fpemu_sp_nmsub;
+ goto scoptop;
+
+ scoptop:
+ SPFROMREG(fr, MIPSInst_FR(ir));
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ SPFROMREG(ft, MIPSInst_FT(ir));
+ fd = (*handler) (fr, fs, ft);
+ SPTOREG(fd, MIPSInst_FD(ir));
+
+ copcsr:
+ if (ieee754_cxtest(IEEE754_INEXACT))
+ rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
+ if (ieee754_cxtest(IEEE754_UNDERFLOW))
+ rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
+ if (ieee754_cxtest(IEEE754_OVERFLOW))
+ rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
+ if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
+ rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
+
+ ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
+ if (ieee754_csr.nod)
+ ctx->fcr31 |= 0x1000000;
+ if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
+ /*printk ("SIGFPE: fpu csr = %08x\n",
+ ctx->fcr31); */
+ return SIGFPE;
+ }
+
+ break;
+
+ default:
+ return SIGILL;
+ }
+ break;
+ }
+
+#ifndef SINGLE_ONLY_FPU
+ case d_fmt:{ /* 1 */
+ ieee754dp(*handler) (ieee754dp, ieee754dp, ieee754dp);
+ ieee754dp fd, fr, fs, ft;
+ u64 *va;
+ u64 val;
+
+ switch (MIPSInst_FUNC(ir)) {
+ case ldxc1_op:
+ va = REG_TO_VA(xcp->regs[MIPSInst_FR(ir)] +
+ xcp->regs[MIPSInst_FT(ir)]);
+
+ fpuemuprivate.stats.loads++;
+ if (get_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ DITOREG(val, MIPSInst_FD(ir));
+ break;
+
+ case sdxc1_op:
+ va = REG_TO_VA(xcp->regs[MIPSInst_FR(ir)] +
+ xcp->regs[MIPSInst_FT(ir)]);
+
+ fpuemuprivate.stats.stores++;
+ DIFROMREG(val, MIPSInst_FS(ir));
+ if (put_user(val, va)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ break;
+
+ case madd_d_op:
+ handler = fpemu_dp_madd;
+ goto dcoptop;
+ case msub_d_op:
+ handler = fpemu_dp_msub;
+ goto dcoptop;
+ case nmadd_d_op:
+ handler = fpemu_dp_nmadd;
+ goto dcoptop;
+ case nmsub_d_op:
+ handler = fpemu_dp_nmsub;
+ goto dcoptop;
+
+ dcoptop:
+ DPFROMREG(fr, MIPSInst_FR(ir));
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ DPFROMREG(ft, MIPSInst_FT(ir));
+ fd = (*handler) (fr, fs, ft);
+ DPTOREG(fd, MIPSInst_FD(ir));
+ goto copcsr;
+
+ default:
+ return SIGILL;
+ }
+ break;
+ }
+#endif
+
+ case 0x7: /* 7 */
+ if (MIPSInst_FUNC(ir) != pfetch_op) {
+ return SIGILL;
+ }
+ /* ignore prefx operation */
+ break;
+
+ default:
+ return SIGILL;
+ }
+
+ return 0;
+}
+#endif
+
+
+
+/*
+ * Emulate a single COP1 arithmetic instruction.
+ */
+static int fpu_emu(struct pt_regs *xcp, struct mips_fpu_soft_struct *ctx,
+ mips_instruction ir)
+{
+ int rfmt; /* resulting format */
+ unsigned rcsr = 0; /* resulting csr */
+ unsigned cond;
+ union {
+ ieee754dp d;
+ ieee754sp s;
+ int w;
+#if __mips64
+ s64 l;
+#endif
+ } rv; /* resulting value */
+
+ fpuemuprivate.stats.cp1ops++;
+ switch (rfmt = (MIPSInst_FFMT(ir) & 0xf)) {
+ case s_fmt:{ /* 0 */
+ union {
+ ieee754sp(*b) (ieee754sp, ieee754sp);
+ ieee754sp(*u) (ieee754sp);
+ } handler;
+
+ switch (MIPSInst_FUNC(ir)) {
+ /* binary ops */
+ case fadd_op:
+ handler.b = ieee754sp_add;
+ goto scopbop;
+ case fsub_op:
+ handler.b = ieee754sp_sub;
+ goto scopbop;
+ case fmul_op:
+ handler.b = ieee754sp_mul;
+ goto scopbop;
+ case fdiv_op:
+ handler.b = ieee754sp_div;
+ goto scopbop;
+
+ /* unary ops */
+#if __mips >= 2 || __mips64
+ case fsqrt_op:
+ handler.u = ieee754sp_sqrt;
+ goto scopuop;
+#endif
+#if __mips >= 4 && __mips != 32
+ case frsqrt_op:
+ handler.u = fpemu_sp_rsqrt;
+ goto scopuop;
+ case frecip_op:
+ handler.u = fpemu_sp_recip;
+ goto scopuop;
+#endif
+#if __mips >= 4
+ case fmovc_op:
+ cond = fpucondbit[MIPSInst_FT(ir) >> 2];
+ if (((ctx->fcr31 & cond) != 0) !=
+ ((MIPSInst_FT(ir) & 1) != 0))
+ return 0;
+ SPFROMREG(rv.s, MIPSInst_FS(ir));
+ break;
+ case fmovz_op:
+ if (xcp->regs[MIPSInst_FT(ir)] != 0)
+ return 0;
+ SPFROMREG(rv.s, MIPSInst_FS(ir));
+ break;
+ case fmovn_op:
+ if (xcp->regs[MIPSInst_FT(ir)] == 0)
+ return 0;
+ SPFROMREG(rv.s, MIPSInst_FS(ir));
+ break;
+#endif
+ case fabs_op:
+ handler.u = ieee754sp_abs;
+ goto scopuop;
+ case fneg_op:
+ handler.u = ieee754sp_neg;
+ goto scopuop;
+ case fmov_op:
+ /* an easy one */
+ SPFROMREG(rv.s, MIPSInst_FS(ir));
+ goto copcsr;
+
+ /* binary op on handler */
+ scopbop:
+ {
+ ieee754sp fs, ft;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ SPFROMREG(ft, MIPSInst_FT(ir));
+
+ rv.s = (*handler.b) (fs, ft);
+ goto copcsr;
+ }
+ scopuop:
+ {
+ ieee754sp fs;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ rv.s = (*handler.u) (fs);
+ goto copcsr;
+ }
+ copcsr:
+ if (ieee754_cxtest(IEEE754_INEXACT))
+ rcsr |= FPU_CSR_INE_X | FPU_CSR_INE_S;
+ if (ieee754_cxtest(IEEE754_UNDERFLOW))
+ rcsr |= FPU_CSR_UDF_X | FPU_CSR_UDF_S;
+ if (ieee754_cxtest(IEEE754_OVERFLOW))
+ rcsr |= FPU_CSR_OVF_X | FPU_CSR_OVF_S;
+ if (ieee754_cxtest(IEEE754_ZERO_DIVIDE))
+ rcsr |= FPU_CSR_DIV_X | FPU_CSR_DIV_S;
+ if (ieee754_cxtest(IEEE754_INVALID_OPERATION))
+ rcsr |= FPU_CSR_INV_X | FPU_CSR_INV_S;
+ break;
+
+ /* unary conv ops */
+ case fcvts_op:
+ return SIGILL; /* not defined */
+ case fcvtd_op:{
+#ifdef SINGLE_ONLY_FPU
+ return SIGILL; /* not defined */
+#else
+ ieee754sp fs;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ rv.d = ieee754dp_fsp(fs);
+ rfmt = d_fmt;
+ goto copcsr;
+ }
+#endif
+ case fcvtw_op:{
+ ieee754sp fs;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ rv.w = ieee754sp_tint(fs);
+ rfmt = w_fmt;
+ goto copcsr;
+ }
+
+#if __mips >= 2 || __mips64
+ case fround_op:
+ case ftrunc_op:
+ case fceil_op:
+ case ffloor_op:{
+ unsigned int oldrm = ieee754_csr.rm;
+ ieee754sp fs;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
+ rv.w = ieee754sp_tint(fs);
+ ieee754_csr.rm = oldrm;
+ rfmt = w_fmt;
+ goto copcsr;
+ }
+#endif /* __mips >= 2 */
+
+#if __mips64 && !defined(SINGLE_ONLY_FPU)
+ case fcvtl_op:{
+ ieee754sp fs;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ rv.l = ieee754sp_tlong(fs);
+ rfmt = l_fmt;
+ goto copcsr;
+ }
+
+ case froundl_op:
+ case ftruncl_op:
+ case fceill_op:
+ case ffloorl_op:{
+ unsigned int oldrm = ieee754_csr.rm;
+ ieee754sp fs;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
+ rv.l = ieee754sp_tlong(fs);
+ ieee754_csr.rm = oldrm;
+ rfmt = l_fmt;
+ goto copcsr;
+ }
+#endif /* __mips64 && !fpu(single) */
+
+ default:
+ if (MIPSInst_FUNC(ir) >= fcmp_op) {
+ unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
+ ieee754sp fs, ft;
+
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ SPFROMREG(ft, MIPSInst_FT(ir));
+ rv.w = ieee754sp_cmp(fs, ft,
+ cmptab[cmpop & 0x7], cmpop & 0x8);
+ rfmt = -1;
+ if ((cmpop & 0x8) && ieee754_cxtest
+ (IEEE754_INVALID_OPERATION))
+ rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
+ else
+ goto copcsr;
+
+ }
+ else {
+ return SIGILL;
+ }
+ break;
+ }
+ break;
+ }
+
+#ifndef SINGLE_ONLY_FPU
+ case d_fmt:{
+ union {
+ ieee754dp(*b) (ieee754dp, ieee754dp);
+ ieee754dp(*u) (ieee754dp);
+ } handler;
+
+ switch (MIPSInst_FUNC(ir)) {
+ /* binary ops */
+ case fadd_op:
+ handler.b = ieee754dp_add;
+ goto dcopbop;
+ case fsub_op:
+ handler.b = ieee754dp_sub;
+ goto dcopbop;
+ case fmul_op:
+ handler.b = ieee754dp_mul;
+ goto dcopbop;
+ case fdiv_op:
+ handler.b = ieee754dp_div;
+ goto dcopbop;
+
+ /* unary ops */
+#if __mips >= 2 || __mips64
+ case fsqrt_op:
+ handler.u = ieee754dp_sqrt;
+ goto dcopuop;
+#endif
+#if __mips >= 4 && __mips != 32
+ case frsqrt_op:
+ handler.u = fpemu_dp_rsqrt;
+ goto dcopuop;
+ case frecip_op:
+ handler.u = fpemu_dp_recip;
+ goto dcopuop;
+#endif
+#if __mips >= 4
+ case fmovc_op:
+ cond = fpucondbit[MIPSInst_FT(ir) >> 2];
+ if (((ctx->fcr31 & cond) != 0) !=
+ ((MIPSInst_FT(ir) & 1) != 0))
+ return 0;
+ DPFROMREG(rv.d, MIPSInst_FS(ir));
+ break;
+ case fmovz_op:
+ if (xcp->regs[MIPSInst_FT(ir)] != 0)
+ return 0;
+ DPFROMREG(rv.d, MIPSInst_FS(ir));
+ break;
+ case fmovn_op:
+ if (xcp->regs[MIPSInst_FT(ir)] == 0)
+ return 0;
+ DPFROMREG(rv.d, MIPSInst_FS(ir));
+ break;
+#endif
+ case fabs_op:
+ handler.u = ieee754dp_abs;
+ goto dcopuop;
+
+ case fneg_op:
+ handler.u = ieee754dp_neg;
+ goto dcopuop;
+
+ case fmov_op:
+ /* an easy one */
+ DPFROMREG(rv.d, MIPSInst_FS(ir));
+ goto copcsr;
+
+ /* binary op on handler */
+ dcopbop:{
+ ieee754dp fs, ft;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ DPFROMREG(ft, MIPSInst_FT(ir));
+
+ rv.d = (*handler.b) (fs, ft);
+ goto copcsr;
+ }
+ dcopuop:{
+ ieee754dp fs;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ rv.d = (*handler.u) (fs);
+ goto copcsr;
+ }
+
+ /* unary conv ops */
+ case fcvts_op:{
+ ieee754dp fs;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ rv.s = ieee754sp_fdp(fs);
+ rfmt = s_fmt;
+ goto copcsr;
+ }
+ case fcvtd_op:
+ return SIGILL; /* not defined */
+
+ case fcvtw_op:{
+ ieee754dp fs;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ rv.w = ieee754dp_tint(fs); /* wrong */
+ rfmt = w_fmt;
+ goto copcsr;
+ }
+
+#if __mips >= 2 || __mips64
+ case fround_op:
+ case ftrunc_op:
+ case fceil_op:
+ case ffloor_op:{
+ unsigned int oldrm = ieee754_csr.rm;
+ ieee754dp fs;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
+ rv.w = ieee754dp_tint(fs);
+ ieee754_csr.rm = oldrm;
+ rfmt = w_fmt;
+ goto copcsr;
+ }
+#endif
+
+#if __mips64 && !defined(SINGLE_ONLY_FPU)
+ case fcvtl_op:{
+ ieee754dp fs;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ rv.l = ieee754dp_tlong(fs);
+ rfmt = l_fmt;
+ goto copcsr;
+ }
+
+ case froundl_op:
+ case ftruncl_op:
+ case fceill_op:
+ case ffloorl_op:{
+ unsigned int oldrm = ieee754_csr.rm;
+ ieee754dp fs;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ ieee754_csr.rm = ieee_rm[MIPSInst_FUNC(ir) & 0x3];
+ rv.l = ieee754dp_tlong(fs);
+ ieee754_csr.rm = oldrm;
+ rfmt = l_fmt;
+ goto copcsr;
+ }
+#endif /* __mips >= 3 && !fpu(single) */
+
+ default:
+ if (MIPSInst_FUNC(ir) >= fcmp_op) {
+ unsigned cmpop = MIPSInst_FUNC(ir) - fcmp_op;
+ ieee754dp fs, ft;
+
+ DPFROMREG(fs, MIPSInst_FS(ir));
+ DPFROMREG(ft, MIPSInst_FT(ir));
+ rv.w = ieee754dp_cmp(fs, ft,
+ cmptab[cmpop & 0x7], cmpop & 0x8);
+ rfmt = -1;
+ if ((cmpop & 0x8)
+ &&
+ ieee754_cxtest
+ (IEEE754_INVALID_OPERATION))
+ rcsr = FPU_CSR_INV_X | FPU_CSR_INV_S;
+ else
+ goto copcsr;
+
+ }
+ else {
+ return SIGILL;
+ }
+ break;
+ }
+ break;
+ }
+#endif /* ifndef SINGLE_ONLY_FPU */
+
+ case w_fmt:{
+ ieee754sp fs;
+
+ switch (MIPSInst_FUNC(ir)) {
+ case fcvts_op:
+ /* convert word to single precision real */
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ rv.s = ieee754sp_fint(fs.bits);
+ rfmt = s_fmt;
+ goto copcsr;
+#ifndef SINGLE_ONLY_FPU
+ case fcvtd_op:
+ /* convert word to double precision real */
+ SPFROMREG(fs, MIPSInst_FS(ir));
+ rv.d = ieee754dp_fint(fs.bits);
+ rfmt = d_fmt;
+ goto copcsr;
+#endif
+ default:
+ return SIGILL;
+ }
+ break;
+ }
+
+#if __mips64 && !defined(SINGLE_ONLY_FPU)
+ case l_fmt:{
+ switch (MIPSInst_FUNC(ir)) {
+ case fcvts_op:
+ /* convert long to single precision real */
+ rv.s = ieee754sp_flong(ctx->fpr[MIPSInst_FS(ir)]);
+ rfmt = s_fmt;
+ goto copcsr;
+ case fcvtd_op:
+ /* convert long to double precision real */
+ rv.d = ieee754dp_flong(ctx->fpr[MIPSInst_FS(ir)]);
+ rfmt = d_fmt;
+ goto copcsr;
+ default:
+ return SIGILL;
+ }
+ break;
+ }
+#endif
+
+ default:
+ return SIGILL;
+ }
+
+ /*
+ * Update the fpu CSR register for this operation.
+ * If an exception is required, generate a tidy SIGFPE exception,
+ * without updating the result register.
+ * Note: cause exception bits do not accumulate, they are rewritten
+ * for each op; only the flag/sticky bits accumulate.
+ */
+ ctx->fcr31 = (ctx->fcr31 & ~FPU_CSR_ALL_X) | rcsr;
+ if ((ctx->fcr31 >> 5) & ctx->fcr31 & FPU_CSR_ALL_E) {
+ /*printk ("SIGFPE: fpu csr = %08x\n",ctx->fcr31); */
+ return SIGFPE;
+ }
+
+ /*
+ * Now we can safely write the result back to the register file.
+ */
+ switch (rfmt) {
+ case -1:{
+#if __mips >= 4
+ cond = fpucondbit[MIPSInst_FD(ir) >> 2];
+#else
+ cond = FPU_CSR_COND;
+#endif
+ if (rv.w)
+ ctx->fcr31 |= cond;
+ else
+ ctx->fcr31 &= ~cond;
+ break;
+ }
+#ifndef SINGLE_ONLY_FPU
+ case d_fmt:
+ DPTOREG(rv.d, MIPSInst_FD(ir));
+ break;
+#endif
+ case s_fmt:
+ SPTOREG(rv.s, MIPSInst_FD(ir));
+ break;
+ case w_fmt:
+ SITOREG(rv.w, MIPSInst_FD(ir));
+ break;
+#if __mips64 && !defined(SINGLE_ONLY_FPU)
+ case l_fmt:
+ DITOREG(rv.l, MIPSInst_FD(ir));
+ break;
+#endif
+ default:
+ return SIGILL;
+ }
+
+ return 0;
+}
+
+int fpu_emulator_cop1Handler(int xcptno, struct pt_regs *xcp,
+ struct mips_fpu_soft_struct *ctx)
+{
+ gpreg_t oldepc, prevepc;
+ mips_instruction insn;
+ int sig = 0;
+
+ oldepc = xcp->cp0_epc;
+ do {
+ prevepc = xcp->cp0_epc;
+
+ if (get_user(insn, (mips_instruction *) xcp->cp0_epc)) {
+ fpuemuprivate.stats.errors++;
+ return SIGBUS;
+ }
+ if (insn == 0)
+ xcp->cp0_epc += 4; /* skip nops */
+ else {
+ /* Update ieee754_csr. Only relevant if we have a
+ h/w FPU */
+ ieee754_csr.nod = (ctx->fcr31 & 0x1000000) != 0;
+ ieee754_csr.rm = ieee_rm[ctx->fcr31 & 0x3];
+ ieee754_csr.cx = (ctx->fcr31 >> 12) & 0x1f;
+ sig = cop1Emulate(xcp, ctx);
+ }
+
+ if (cpu_has_fpu)
+ break;
+ if (sig)
+ break;
+
+ cond_resched();
+ } while (xcp->cp0_epc > prevepc);
+
+ /* SIGILL indicates a non-fpu instruction */
+ if (sig == SIGILL && xcp->cp0_epc != oldepc)
+ /* but if epc has advanced, then ignore it */
+ sig = 0;
+
+ return sig;
+}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-19 09:14:15 +0000