Commit 5bde1407 authored by Pavel Dovgalyuk's avatar Pavel Dovgalyuk Committed by Paolo Bonzini
Browse files

target-i386: update fp status fix 



This patch introduces cpu_set_fpuc() function, which changes fpuc field
of the CPU state and calls update_fp_status() function.
These calls update status of softfloat library and prevent bugs caused
by non-coherent rounding settings of the FPU and softfloat.

v2 changes:
 * Added missed calls and intoduced setter function (as suggested by TeLeMan)

Reviewed-by: default avatarTeLeMan <geleman@gmail.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarPavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
parent 7dbb4c49

target-i386/cpu.c

+1 −1
Original line number Diff line number Diff line
@@ -2580,7 +2580,7 @@ static void x86_cpu_reset(CPUState *s) 
    for (i = 0; i < 8; i++) {

        env->fptags[i] = 1;

    }

    env->fpuc = 0x37f;

    cpu_set_fpuc(env, 0x37f);



    env->mxcsr = 0x1f80;

    env->xstate_bv = XSTATE_FP | XSTATE_SSE;

target-i386/cpu.h

+2 −0
Original line number Diff line number Diff line
@@ -1251,6 +1251,7 @@ void QEMU_NORETURN raise_interrupt(CPUX86State *nenv, int intno, int is_int, 
/* cc_helper.c */

extern const uint8_t parity_table[256];

uint32_t cpu_cc_compute_all(CPUX86State *env1, int op);

void update_fp_status(CPUX86State *env);



static inline uint32_t cpu_compute_eflags(CPUX86State *env)

{
@@ -1286,6 +1287,7 @@ static inline void cpu_load_efer(CPUX86State *env, uint64_t val) 


/* fpu_helper.c */

void cpu_set_mxcsr(CPUX86State *env, uint32_t val);

void cpu_set_fpuc(CPUX86State *env, uint16_t val);



/* svm_helper.c */

void cpu_svm_check_intercept_param(CPUX86State *env1, uint32_t type,

target-i386/fpu_helper.c

+13 −8
Original line number Diff line number Diff line
@@ -537,7 +537,7 @@ uint32_t helper_fnstcw(CPUX86State *env) 
    return env->fpuc;

}



static void update_fp_status(CPUX86State *env)

void update_fp_status(CPUX86State *env)

{

    int rnd_type;
@@ -575,8 +575,7 @@ static void update_fp_status(CPUX86State *env) 


void helper_fldcw(CPUX86State *env, uint32_t val)

{

    env->fpuc = val;

    update_fp_status(env);

    cpu_set_fpuc(env, val);

}



void helper_fclex(CPUX86State *env)
@@ -595,7 +594,7 @@ void helper_fninit(CPUX86State *env) 
{

    env->fpus = 0;

    env->fpstt = 0;

    env->fpuc = 0x37f;

    cpu_set_fpuc(env, 0x37f);

    env->fptags[0] = 1;

    env->fptags[1] = 1;

    env->fptags[2] = 1;
@@ -1013,11 +1012,11 @@ void helper_fldenv(CPUX86State *env, target_ulong ptr, int data32) 
    int i, fpus, fptag;



    if (data32) {

        env->fpuc = cpu_lduw_data(env, ptr);

        cpu_set_fpuc(env, cpu_lduw_data(env, ptr));

        fpus = cpu_lduw_data(env, ptr + 4);

        fptag = cpu_lduw_data(env, ptr + 8);

    } else {

        env->fpuc = cpu_lduw_data(env, ptr);

        cpu_set_fpuc(env, cpu_lduw_data(env, ptr));

        fpus = cpu_lduw_data(env, ptr + 2);

        fptag = cpu_lduw_data(env, ptr + 4);

    }
@@ -1046,7 +1045,7 @@ void helper_fsave(CPUX86State *env, target_ulong ptr, int data32) 
    /* fninit */

    env->fpus = 0;

    env->fpstt = 0;

    env->fpuc = 0x37f;

    cpu_set_fpuc(env, 0x37f);

    env->fptags[0] = 1;

    env->fptags[1] = 1;

    env->fptags[2] = 1;
@@ -1157,7 +1156,7 @@ void helper_fxrstor(CPUX86State *env, target_ulong ptr, int data64) 
        raise_exception(env, EXCP0D_GPF);

    }



    env->fpuc = cpu_lduw_data(env, ptr);

    cpu_set_fpuc(env, cpu_lduw_data(env, ptr));

    fpus = cpu_lduw_data(env, ptr + 2);

    fptag = cpu_lduw_data(env, ptr + 4);

    env->fpstt = (fpus >> 11) & 7;
@@ -1257,6 +1256,12 @@ void cpu_set_mxcsr(CPUX86State *env, uint32_t mxcsr) 
    set_flush_to_zero((mxcsr & SSE_FZ) ? 1 : 0, &env->fp_status);

}



void cpu_set_fpuc(CPUX86State *env, uint16_t val)

{

    env->fpuc = val;

    update_fp_status(env);

}



void helper_ldmxcsr(CPUX86State *env, uint32_t val)

{

    cpu_set_mxcsr(env, val);

target-i386/gdbstub.c

+1 −1
Original line number Diff line number Diff line
@@ -203,7 +203,7 @@ int x86_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n) 
            return x86_cpu_gdb_load_seg(cpu, R_GS, mem_buf);



        case IDX_FP_REGS + 8:

            env->fpuc = ldl_p(mem_buf);

            cpu_set_fpuc(env, ldl_p(mem_buf));

            return 4;

        case IDX_FP_REGS + 9:

            tmp = ldl_p(mem_buf);

target-i386/machine.c

+1 −1
Original line number Diff line number Diff line
@@ -315,13 +315,13 @@ static int cpu_post_load(void *opaque, int version_id) 
    env->hflags &= ~HF_CPL_MASK;

    env->hflags |= (env->segs[R_SS].flags >> DESC_DPL_SHIFT) & HF_CPL_MASK;



    /* XXX: restore FPU round state */

    env->fpstt = (env->fpus_vmstate >> 11) & 7;

    env->fpus = env->fpus_vmstate & ~0x3800;

    env->fptag_vmstate ^= 0xff;

    for(i = 0; i < 8; i++) {

        env->fptags[i] = (env->fptag_vmstate >> i) & 1;

    }

    update_fp_status(env);



    cpu_breakpoint_remove_all(cs, BP_CPU);

    cpu_watchpoint_remove_all(cs, BP_CPU);