X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/119bdfc4c80e313417047de10700e6b8c3955d0d..1b07c4f340465551b7d12c3be3bcecd258a3c32d:/base/dispatch-x86ish.S

diff --git a/base/dispatch-x86ish.S b/base/dispatch-x86ish.S
index 2c267b62..b3b6d1cb 100644
--- a/base/dispatch-x86ish.S
+++ b/base/dispatch-x86ish.S
@@ -46,9 +46,9 @@ FUNC(dispatch_x86ish_cpuid)
 #if CPUFAM_X86
 	pushreg	ebx
 	pushreg	edi
-	mov	edi, [esp + 12]
-	mov	eax, [esp + 16]
-	mov	ecx, [esp + 20]
+	mov	edi, [SP + 12]
+	mov	eax, [SP + 16]
+	mov	ecx, [SP + 20]
 #  define OUT edi
 #endif
 #if CPUFAM_AMD64 && ABI_SYSV
@@ -69,21 +69,21 @@ FUNC(dispatch_x86ish_cpuid)
 	// First, check that this is even a thing, using the complicated
 	// dance with the flags register.
 	pushf
-	pop	R_d(r)			// current flags in d
+	pop	DX			// current flags in d
 
-	or	R_d(r), EFLAGS_ID	// force the id bit on and check it
-	push	R_d(r)
+	or	DX, EFLAGS_ID		// force the id bit on and check it
+	push	DX
 	popf
 	pushf
-	pop	R_d(r)
+	pop	DX
 	test	edx, EFLAGS_ID
 	jz	8f
 
-	and	R_d(r), ~EFLAGS_ID	// force the id bit off and check it
-	push	R_d(r)
+	and	DX, ~EFLAGS_ID		// force the id bit off and check it
+	push	DX
 	popf
 	pushf
-	pop	R_d(r)
+	pop	DX
 	test	edx, EFLAGS_ID
 	jnz	8f
 
@@ -124,33 +124,83 @@ FUNC(dispatch_x86ish_xmmregisters_p)
 	// Enter with no arguments.  Return nonzero if the XMM registers are
 	// usable.
 
-	pushreg	R_bp(r)
+	pushreg	BP
 	setfp
 	stalloc	512
-	and	R_sp(r), ~15
+	and	SP, ~15
   endprologue
 
 	// Save the floating point and SIMD registers, and try to clobber
 	// xmm0.
-	fxsave	[R_sp(r)]
-	mov	eax, [R_sp(r) + 160]
-	xor	dword ptr [R_sp(r) + 160], 0xaaaa5555
-	fxrstor	[R_sp(r)]
+	lea	DX, [SP + 160]
+	fxsave	[SP]
+	mov	eax, [DX]
+	xor	dword ptr [DX], 0xaaaa5555
+	fxrstor	[SP]
 
 	// Save them again, and read back the low word of xmm0.  Undo the
 	// clobbering and restore.
-	fxsave	[R_sp(r)]
-	mov	ecx, [R_sp(r) + 160]
-	mov	[R_sp(r) + 160], eax
-	fxrstor	[R_sp(r)]
+	fxsave	[SP]
+	mov	ecx, [DX]
+	mov	[DX], eax
+	fxrstor	[SP]
 
 	// The register are live if we read different things.
 	xor	eax, ecx
 
 	// Done.
 	dropfp
-	popreg	R_bp(r)
+	popreg	BP
 	ret
 ENDFUNC
 
+///--------------------------------------------------------------------------
+/// Checking `rdrand'.
+
+FUNC(dispatch_x86ish_rdrand)
+	// Enter with two arguments: a code OP requesting `rdrand' (0), and a
+	// pointer X_OUT to a 32-bit word.  Try to generate a random word
+	// using the requested instruction.  If successful, set *X_OUT to the
+	// generated word, and return zero; otherwise, return -1.
+
+#if CPUFAM_X86
+#  define OP eax
+#  define X_OUT edx
+#  define COUNT ecx
+	mov	OP, [SP + 4]
+	mov	X_OUT, [SP + 8]
+#endif
+#if CPUFAM_AMD64 && ABI_SYSV
+#  define OP edi
+#  define X_OUT rsi
+#  define COUNT ecx
+#endif
+#if CPUFAM_AMD64 && ABI_WIN
+#  define OP rcx
+#  define X_OUT rdx
+#  define COUNT r8d
+#endif
+  endprologue
+
+	mov	COUNT, 16		// fairly persistent
+0:	rdrand	eax
+	jc	9f
+	dec	COUNT
+	jnz	0b
+	jmp	8f
+
+	// Failed to come up with a random value.
+8:	mov	eax, -1
+	ret
+
+	// Success.
+9:	mov	[X_OUT], eax
+	xor	eax, eax
+	ret
+
+#undef X_OUT
+#undef COUNT
+
+ENDFUNC
+
 ///----- That's all, folks --------------------------------------------------