diff options
Diffstat (limited to 'kernel/arch/alpha/math-emu/math.c')
| -rw-r--r-- | kernel/arch/alpha/math-emu/math.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/kernel/arch/alpha/math-emu/math.c b/kernel/arch/alpha/math-emu/math.c new file mode 100644 index 000000000..58c2669a1 --- /dev/null +++ b/kernel/arch/alpha/math-emu/math.c @@ -0,0 +1,400 @@ +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/sched.h> + +#include <asm/uaccess.h> + +#include "sfp-util.h" +#include <math-emu/soft-fp.h> +#include <math-emu/single.h> +#include <math-emu/double.h> + +#define OPC_PAL 0x00 +#define OPC_INTA 0x10 +#define OPC_INTL 0x11 +#define OPC_INTS 0x12 +#define OPC_INTM 0x13 +#define OPC_FLTC 0x14 +#define OPC_FLTV 0x15 +#define OPC_FLTI 0x16 +#define OPC_FLTL 0x17 +#define OPC_MISC 0x18 +#define OPC_JSR 0x1a + +#define FOP_SRC_S 0 +#define FOP_SRC_T 2 +#define FOP_SRC_Q 3 + +#define FOP_FNC_ADDx 0 +#define FOP_FNC_CVTQL 0 +#define FOP_FNC_SUBx 1 +#define FOP_FNC_MULx 2 +#define FOP_FNC_DIVx 3 +#define FOP_FNC_CMPxUN 4 +#define FOP_FNC_CMPxEQ 5 +#define FOP_FNC_CMPxLT 6 +#define FOP_FNC_CMPxLE 7 +#define FOP_FNC_SQRTx 11 +#define FOP_FNC_CVTxS 12 +#define FOP_FNC_CVTxT 14 +#define FOP_FNC_CVTxQ 15 + +#define MISC_TRAPB 0x0000 +#define MISC_EXCB 0x0400 + +extern unsigned long alpha_read_fp_reg (unsigned long reg); +extern void alpha_write_fp_reg (unsigned long reg, unsigned long val); +extern unsigned long alpha_read_fp_reg_s (unsigned long reg); +extern void alpha_write_fp_reg_s (unsigned long reg, unsigned long val); + + +#ifdef MODULE + +MODULE_DESCRIPTION("FP Software completion module"); + +extern long (*alpha_fp_emul_imprecise)(struct pt_regs *, unsigned long); +extern long (*alpha_fp_emul) (unsigned long pc); + +static long (*save_emul_imprecise)(struct pt_regs *, unsigned long); +static long (*save_emul) (unsigned long pc); + +long do_alpha_fp_emul_imprecise(struct pt_regs *, unsigned long); +long do_alpha_fp_emul(unsigned long); + +int init_module(void) +{ + save_emul_imprecise = alpha_fp_emul_imprecise; + save_emul = alpha_fp_emul; + alpha_fp_emul_imprecise = do_alpha_fp_emul_imprecise; + alpha_fp_emul = do_alpha_fp_emul; + return 0; +} + +void cleanup_module(void) +{ + alpha_fp_emul_imprecise = save_emul_imprecise; + alpha_fp_emul = save_emul; +} + +#undef alpha_fp_emul_imprecise +#define alpha_fp_emul_imprecise do_alpha_fp_emul_imprecise +#undef alpha_fp_emul +#define alpha_fp_emul do_alpha_fp_emul + +#endif /* MODULE */ + + +/* + * Emulate the floating point instruction at address PC. Returns -1 if the + * instruction to be emulated is illegal (such as with the opDEC trap), else + * the SI_CODE for a SIGFPE signal, else 0 if everything's ok. + * + * Notice that the kernel does not and cannot use FP regs. This is good + * because it means that instead of saving/restoring all fp regs, we simply + * stick the result of the operation into the appropriate register. + */ +long +alpha_fp_emul (unsigned long pc) +{ + FP_DECL_EX; + FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR); + FP_DECL_D(DA); FP_DECL_D(DB); FP_DECL_D(DR); + + unsigned long fa, fb, fc, func, mode, src; + unsigned long res, va, vb, vc, swcr, fpcr; + __u32 insn; + long si_code; + + get_user(insn, (__u32 __user *)pc); + fc = (insn >> 0) & 0x1f; /* destination register */ + fb = (insn >> 16) & 0x1f; + fa = (insn >> 21) & 0x1f; + func = (insn >> 5) & 0xf; + src = (insn >> 9) & 0x3; + mode = (insn >> 11) & 0x3; + + fpcr = rdfpcr(); + swcr = swcr_update_status(current_thread_info()->ieee_state, fpcr); + + if (mode == 3) { + /* Dynamic -- get rounding mode from fpcr. */ + mode = (fpcr >> FPCR_DYN_SHIFT) & 3; + } + + switch (src) { + case FOP_SRC_S: + va = alpha_read_fp_reg_s(fa); + vb = alpha_read_fp_reg_s(fb); + + FP_UNPACK_SP(SA, &va); + FP_UNPACK_SP(SB, &vb); + + switch (func) { + case FOP_FNC_SUBx: + FP_SUB_S(SR, SA, SB); + goto pack_s; + + case FOP_FNC_ADDx: + FP_ADD_S(SR, SA, SB); + goto pack_s; + + case FOP_FNC_MULx: + FP_MUL_S(SR, SA, SB); + goto pack_s; + + case FOP_FNC_DIVx: + FP_DIV_S(SR, SA, SB); + goto pack_s; + + case FOP_FNC_SQRTx: + FP_SQRT_S(SR, SB); + goto pack_s; + } + goto bad_insn; + + case FOP_SRC_T: + va = alpha_read_fp_reg(fa); + vb = alpha_read_fp_reg(fb); + + if ((func & ~3) == FOP_FNC_CMPxUN) { + FP_UNPACK_RAW_DP(DA, &va); + FP_UNPACK_RAW_DP(DB, &vb); + if (!DA_e && !_FP_FRAC_ZEROP_1(DA)) { + FP_SET_EXCEPTION(FP_EX_DENORM); + if (FP_DENORM_ZERO) + _FP_FRAC_SET_1(DA, _FP_ZEROFRAC_1); + } + if (!DB_e && !_FP_FRAC_ZEROP_1(DB)) { + FP_SET_EXCEPTION(FP_EX_DENORM); + if (FP_DENORM_ZERO) + _FP_FRAC_SET_1(DB, _FP_ZEROFRAC_1); + } + FP_CMP_D(res, DA, DB, 3); + vc = 0x4000000000000000UL; + /* CMPTEQ, CMPTUN don't trap on QNaN, + while CMPTLT and CMPTLE do */ + if (res == 3 + && ((func & 3) >= 2 + || FP_ISSIGNAN_D(DA) + || FP_ISSIGNAN_D(DB))) { + FP_SET_EXCEPTION(FP_EX_INVALID); + } + switch (func) { + case FOP_FNC_CMPxUN: if (res != 3) vc = 0; break; + case FOP_FNC_CMPxEQ: if (res) vc = 0; break; + case FOP_FNC_CMPxLT: if (res != -1) vc = 0; break; + case FOP_FNC_CMPxLE: if ((long)res > 0) vc = 0; break; + } + goto done_d; + } + + FP_UNPACK_DP(DA, &va); + FP_UNPACK_DP(DB, &vb); + + switch (func) { + case FOP_FNC_SUBx: + FP_SUB_D(DR, DA, DB); + goto pack_d; + + case FOP_FNC_ADDx: + FP_ADD_D(DR, DA, DB); + goto pack_d; + + case FOP_FNC_MULx: + FP_MUL_D(DR, DA, DB); + goto pack_d; + + case FOP_FNC_DIVx: + FP_DIV_D(DR, DA, DB); + goto pack_d; + + case FOP_FNC_SQRTx: + FP_SQRT_D(DR, DB); + goto pack_d; + + case FOP_FNC_CVTxS: + /* It is irritating that DEC encoded CVTST with + SRC == T_floating. It is also interesting that + the bit used to tell the two apart is /U... */ + if (insn & 0x2000) { + FP_CONV(S,D,1,1,SR,DB); + goto pack_s; + } else { + vb = alpha_read_fp_reg_s(fb); + FP_UNPACK_SP(SB, &vb); + DR_c = DB_c; + DR_s = DB_s; + DR_e = DB_e + (1024 - 128); + DR_f = SB_f << (52 - 23); + goto pack_d; + } + + case FOP_FNC_CVTxQ: + if (DB_c == FP_CLS_NAN + && (_FP_FRAC_HIGH_RAW_D(DB) & _FP_QNANBIT_D)) { + /* AAHB Table B-2 says QNaN should not trigger INV */ + vc = 0; + } else + FP_TO_INT_ROUND_D(vc, DB, 64, 2); + goto done_d; + } + goto bad_insn; + + case FOP_SRC_Q: + vb = alpha_read_fp_reg(fb); + + switch (func) { + case FOP_FNC_CVTQL: + /* Notice: We can get here only due to an integer + overflow. Such overflows are reported as invalid + ops. We return the result the hw would have + computed. */ + vc = ((vb & 0xc0000000) << 32 | /* sign and msb */ + (vb & 0x3fffffff) << 29); /* rest of the int */ + FP_SET_EXCEPTION (FP_EX_INVALID); + goto done_d; + + case FOP_FNC_CVTxS: + FP_FROM_INT_S(SR, ((long)vb), 64, long); + goto pack_s; + + case FOP_FNC_CVTxT: + FP_FROM_INT_D(DR, ((long)vb), 64, long); + goto pack_d; + } + goto bad_insn; + } + goto bad_insn; + +pack_s: + FP_PACK_SP(&vc, SR); + if ((_fex & FP_EX_UNDERFLOW) && (swcr & IEEE_MAP_UMZ)) + vc = 0; + alpha_write_fp_reg_s(fc, vc); + goto done; + +pack_d: + FP_PACK_DP(&vc, DR); + if ((_fex & FP_EX_UNDERFLOW) && (swcr & IEEE_MAP_UMZ)) + vc = 0; +done_d: + alpha_write_fp_reg(fc, vc); + goto done; + + /* + * Take the appropriate action for each possible + * floating-point result: + * + * - Set the appropriate bits in the FPCR + * - If the specified exception is enabled in the FPCR, + * return. The caller (entArith) will dispatch + * the appropriate signal to the translated program. + * + * In addition, properly track the exception state in software + * as described in the Alpha Architecture Handbook section 4.7.7.3. + */ +done: + if (_fex) { + /* Record exceptions in software control word. */ + swcr |= (_fex << IEEE_STATUS_TO_EXCSUM_SHIFT); + current_thread_info()->ieee_state + |= (_fex << IEEE_STATUS_TO_EXCSUM_SHIFT); + + /* Update hardware control register. */ + fpcr &= (~FPCR_MASK | FPCR_DYN_MASK); + fpcr |= ieee_swcr_to_fpcr(swcr); + wrfpcr(fpcr); + + /* Do we generate a signal? */ + _fex = _fex & swcr & IEEE_TRAP_ENABLE_MASK; + si_code = 0; + if (_fex) { + if (_fex & IEEE_TRAP_ENABLE_DNO) si_code = FPE_FLTUND; + if (_fex & IEEE_TRAP_ENABLE_INE) si_code = FPE_FLTRES; + if (_fex & IEEE_TRAP_ENABLE_UNF) si_code = FPE_FLTUND; + if (_fex & IEEE_TRAP_ENABLE_OVF) si_code = FPE_FLTOVF; + if (_fex & IEEE_TRAP_ENABLE_DZE) si_code = FPE_FLTDIV; + if (_fex & IEEE_TRAP_ENABLE_INV) si_code = FPE_FLTINV; + } + + return si_code; + } + + /* We used to write the destination register here, but DEC FORTRAN + requires that the result *always* be written... so we do the write + immediately after the operations above. */ + + return 0; + +bad_insn: + printk(KERN_ERR "alpha_fp_emul: Invalid FP insn %#x at %#lx\n", + insn, pc); + return -1; +} + +long +alpha_fp_emul_imprecise (struct pt_regs *regs, unsigned long write_mask) +{ + unsigned long trigger_pc = regs->pc - 4; + unsigned long insn, opcode, rc, si_code = 0; + + /* + * Turn off the bits corresponding to registers that are the + * target of instructions that set bits in the exception + * summary register. We have some slack doing this because a + * register that is the target of a trapping instruction can + * be written at most once in the trap shadow. + * + * Branches, jumps, TRAPBs, EXCBs and calls to PALcode all + * bound the trap shadow, so we need not look any further than + * up to the first occurrence of such an instruction. + */ + while (write_mask) { + get_user(insn, (__u32 __user *)(trigger_pc)); + opcode = insn >> 26; + rc = insn & 0x1f; + + switch (opcode) { + case OPC_PAL: + case OPC_JSR: + case 0x30 ... 0x3f: /* branches */ + goto egress; + + case OPC_MISC: + switch (insn & 0xffff) { + case MISC_TRAPB: + case MISC_EXCB: + goto egress; + + default: + break; + } + break; + + case OPC_INTA: + case OPC_INTL: + case OPC_INTS: + case OPC_INTM: + write_mask &= ~(1UL << rc); + break; + + case OPC_FLTC: + case OPC_FLTV: + case OPC_FLTI: + case OPC_FLTL: + write_mask &= ~(1UL << (rc + 32)); + break; + } + if (!write_mask) { + /* Re-execute insns in the trap-shadow. */ + regs->pc = trigger_pc + 4; + si_code = alpha_fp_emul(trigger_pc); + goto egress; + } + trigger_pc -= 4; + } + +egress: + return si_code; +} |