target-mips: add Config5.FRE support allowing Status.FR=0 emulation

This relatively small architectural feature adds the following:

FIR.FREP: Read-only. If FREP=1, then Config5.FRE and Config5.UFE are
          available.

Config5.FRE: When enabled all single-precision FP arithmetic instructions,
             LWC1/LWXC1/MTC1, SWC1/SWXC1/MFC1 cause a Reserved Instructions
             exception.

Config5.UFE: Allows user to write/read Config5.FRE using CTC1/CFC1
             instructions.

Enable the feature in MIPS64R6-generic CPU.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
This commit is contained in:
Leon Alrae 2015-04-21 16:06:28 +01:00
parent eab9944c78
commit 7c979afd11
4 changed files with 208 additions and 156 deletions

View file

@ -100,6 +100,7 @@ struct CPUMIPSFPUContext {
float_status fp_status;
/* fpu implementation/revision register (fir) */
uint32_t fcr0;
#define FCR0_FREP 29
#define FCR0_UFRP 28
#define FCR0_F64 22
#define FCR0_L 21
@ -462,6 +463,8 @@ struct CPUMIPSState {
#define CP0C5_CV 29
#define CP0C5_EVA 28
#define CP0C5_MSAEn 27
#define CP0C5_UFE 9
#define CP0C5_FRE 8
#define CP0C5_SBRI 6
#define CP0C5_UFR 2
#define CP0C5_NFExists 0
@ -514,7 +517,7 @@ struct CPUMIPSState {
#define EXCP_INST_NOTAVAIL 0x2 /* No valid instruction word for BadInstr */
uint32_t hflags; /* CPU State */
/* TMASK defines different execution modes */
#define MIPS_HFLAG_TMASK 0x15807FF
#define MIPS_HFLAG_TMASK 0x35807FF
#define MIPS_HFLAG_MODE 0x00007 /* execution modes */
/* The KSU flags must be the lowest bits in hflags. The flag order
must be the same as defined for CP0 Status. This allows to use
@ -561,6 +564,7 @@ struct CPUMIPSState {
#define MIPS_HFLAG_SBRI 0x400000 /* R6 SDBBP causes RI excpt. in user mode */
#define MIPS_HFLAG_FBNSLOT 0x800000 /* Forbidden slot */
#define MIPS_HFLAG_MSA 0x1000000
#define MIPS_HFLAG_FRE 0x2000000 /* FRE enabled */
target_ulong btarget; /* Jump / branch target */
target_ulong bcond; /* Branch condition (if needed) */
@ -843,7 +847,7 @@ static inline void compute_hflags(CPUMIPSState *env)
env->hflags &= ~(MIPS_HFLAG_COP1X | MIPS_HFLAG_64 | MIPS_HFLAG_CP0 |
MIPS_HFLAG_F64 | MIPS_HFLAG_FPU | MIPS_HFLAG_KSU |
MIPS_HFLAG_AWRAP | MIPS_HFLAG_DSP | MIPS_HFLAG_DSPR2 |
MIPS_HFLAG_SBRI | MIPS_HFLAG_MSA);
MIPS_HFLAG_SBRI | MIPS_HFLAG_MSA | MIPS_HFLAG_FRE);
if (!(env->CP0_Status & (1 << CP0St_EXL)) &&
!(env->CP0_Status & (1 << CP0St_ERL)) &&
!(env->hflags & MIPS_HFLAG_DM)) {
@ -924,6 +928,11 @@ static inline void compute_hflags(CPUMIPSState *env)
env->hflags |= MIPS_HFLAG_MSA;
}
}
if (env->active_fpu.fcr0 & (1 << FCR0_FREP)) {
if (env->CP0_Config5 & (1 << CP0C5_FRE)) {
env->hflags |= MIPS_HFLAG_FRE;
}
}
}
#ifndef CONFIG_USER_ONLY