Attachment 218882 Details for Bug 250454 – Proposed patch

[patch] Proposed patch

ftw.diff (text/plain), 3.05 KB, created by Michał Górny on 2020-10-19 09:48:22 UTC

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Creator: Michał Górny

Created: 2020-10-19 09:48:22 UTC

Size: 3.05 KB

patch

obsolete

>diff --git a/sys/amd64/ia32/ia32_reg.c b/sys/amd64/ia32/ia32_reg.c
>index 4a068b7f61e..10c91f9c0b9 100644
>--- a/sys/amd64/ia32/ia32_reg.c
>+++ b/sys/amd64/ia32/ia32_reg.c
>@@ -146,7 +146,9 @@ fill_fpregs32(struct thread *td, struct fpreg32 *regs)
> 	struct save87 *sv_87;
> 	struct env87 *penv_87;
> 	struct envxmm *penv_xmm;
>-	int i;
>+	int i, st;
>+	uint16_t tw;
>+	uint8_t ab_tw;
> 
> 	bzero(regs, sizeof(*regs));
> 	sv_87 = (struct save87 *)regs;
>@@ -173,12 +175,30 @@ fill_fpregs32(struct thread *td, struct fpreg32 *regs)
> 	penv_87->en_fos = td->td_frame->tf_ds;
> 
> 	/* FPU registers and tags */
>-	penv_87->en_tw = 0xffff;
>-	for (i = 0; i < 8; ++i) {
>-		sv_87->sv_ac[i] = sv_fpu->sv_fp[i].fp_acc;
>-		if ((penv_xmm->en_tw & (1 << i)) != 0)
>-			penv_87->en_tw &= ~(3 << i * 2);
>+	/* For ST(i), i = fpu_reg - top, we start with fpu_reg=7. */
>+	st = 7 - ((penv_xmm->en_sw >> 11) & 7);
>+	ab_tw = penv_xmm->en_tw;
>+	tw = 0;
>+	for (i = 0x80; i != 0; i >>= 1) {
>+		sv_87->sv_ac[st] = sv_fpu->sv_fp[st].fp_acc;
>+		tw <<= 2;
>+		if (ab_tw & i) {
>+			/* Non-empty - we need to check ST(i) */
>+			struct fpacc87* fx_reg = &sv_fpu->sv_fp[st].fp_acc;
>+			uint16_t exp = *((uint16_t*)&fx_reg->fp_bytes[8]) & 0x7fff;
>+			uint64_t mantissa = *((uint64_t*)fx_reg->fp_bytes);
>+			if (exp == 0) {
>+				if (mantissa == 0)
>+					tw |= 1; /* Zero */
>+				else
>+					tw |= 2; /* Denormal */
>+			} else if (exp == 0x7fff)
>+				tw |= 2; /* Infinity or NaN */
>+		} else
>+			tw |= 3; /* Empty */
>+		st = (st - 1) & 7;
> 	}
>+	penv_87->en_tw = tw;
> 
> 	return (0);
> }
>diff --git a/sys/i386/i386/npx.c b/sys/i386/i386/npx.c
>index d5ce4fe5513..285b2bf58d1 100644
>--- a/sys/i386/i386/npx.c
>+++ b/sys/i386/i386/npx.c
>@@ -1149,7 +1149,9 @@ npx_fill_fpregs_xmm1(struct savexmm *sv_xmm, struct save87 *sv_87)
> {
> 	struct env87 *penv_87;
> 	struct envxmm *penv_xmm;
>-	int i;
>+	int i, st;
>+	uint8_t ab_tw;
>+	uint16_t tw;
> 
> 	penv_87 = &sv_87->sv_env;
> 	penv_xmm = &sv_xmm->sv_env;
>@@ -1164,13 +1166,31 @@ npx_fill_fpregs_xmm1(struct savexmm *sv_xmm, struct save87 *sv_87)
> 	penv_87->en_fos = penv_xmm->en_fos;
> 
> 	/* FPU registers and tags */
>-	penv_87->en_tw = 0xffff;
>-	for (i = 0; i < 8; ++i) {
>-		sv_87->sv_ac[i] = sv_xmm->sv_fp[i].fp_acc;
>-		if ((penv_xmm->en_tw & (1 << i)) != 0)
>-			/* zero and special are set as valid */
>-			penv_87->en_tw &= ~(3 << i * 2);
>+	/* For ST(i), i = fpu_reg - top, we start with fpu_reg=7. */
>+	st = 7 - ((penv_xmm->en_sw >> 11) & 7);
>+	ab_tw = penv_xmm->en_tw;
>+	tw = 0;
>+	for (i = 0x80; i != 0; i >>= 1) {
>+		sv_87->sv_ac[st] = sv_xmm->sv_fp[st].fp_acc;
>+		tw <<= 2;
>+		if (ab_tw & i) {
>+			/* Non-empty - we need to check ST(i) */
>+			struct fpacc87* fx_reg = &sv_xmm->sv_fp[st].fp_acc;
>+			uint16_t exp = *((uint16_t*)fx_reg) & 0x7fff;
>+			uint16_t exp = *((uint16_t*)&fx_reg->fp_bytes[8]) & 0x7fff;
>+			uint64_t mantissa = *((uint64_t*)fx_reg->fp_bytes);
>+			if (exp == 0) {
>+				if (mantissa == 0)
>+					tw |= 1; /* Zero */
>+				else
>+					tw |= 2; /* Denormal */
>+			} else if (exp == 0x7fff)
>+				tw |= 2; /* Infinity or NaN */
>+		} else
>+			tw |= 3; /* Empty */
>+		st = (st - 1) & 7;
> 	}
>+	penv_87->en_tw = tw;
> }
> 
> void

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Attachments on bug 250454: 218882