Rewrite the JDIMENSION argument management for x86 64-bit assembly to

simd/jcqnts2i-64.asm

 ;
 ; jcqnts2i-64.asm - sample data conversion and quantization (64-bit SSE2)
 ;
 ; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
 ; Copyright 2009 D. R. Commander
 ;
 ; Based on
 ; x86 SIMD extension for IJG JPEG library
 ; Copyright (C) 1999-2006, MIYASAKA Masaru.
 ; For conditions of distribution and use, see copyright notice in jsimdext.inc
@@ skipping 32 matching lines @@
         mov     rax,rsp
         mov     rbp,rsp
         collect_args
         push    rbx
 
         pxor    xmm6,xmm6               ; xmm6=(all 0's)
         pcmpeqw xmm7,xmm7
         psllw   xmm7,7                  ; xmm7={0xFF80 0xFF80 0xFF80 0xFF80 ..}
 
         mov rsi, r10
-        mov rax, r11
+        mov eax, r11d
         mov rdi, r12
         mov     rcx, DCTSIZE/4
 .convloop:
         mov     rbx, JSAMPROW [rsi+0*SIZEOF_JSAMPROW]   ; (JSAMPLE *)
         mov rdx, JSAMPROW [rsi+1*SIZEOF_JSAMPROW]       ; (JSAMPLE *)
 
         movq    xmm0, XMM_MMWORD [rbx+rax*SIZEOF_JSAMPLE]       ; xmm0=(01234567)
         movq    xmm1, XMM_MMWORD [rdx+rax*SIZEOF_JSAMPLE]       ; xmm1=(89ABCDEF)
 
         mov     rbx, JSAMPROW [rsi+2*SIZEOF_JSAMPROW]   ; (JSAMPLE *)
@@ skipping 114 matching lines @@
         dec     rax
         jnz     near .quantloop
 
         uncollect_args
         pop     rbp
         ret
 
 ; For some reason, the OS X linker does not honor the request to align the
 ; segment unless we do this.
         align   16