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

simd/jcsamss2-64.asm

 ;
 ; jcsamss2-64.asm - downsampling (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 31 matching lines @@
 
         align   16
         global  EXTN(jsimd_h2v1_downsample_sse2) PRIVATE
 
 EXTN(jsimd_h2v1_downsample_sse2):
         push    rbp
         mov     rax,rsp
         mov     rbp,rsp
         collect_args
 
-        mov rcx, r13
+        mov ecx, r13d
         shl     rcx,3                   ; imul rcx,DCTSIZE (rcx = output_cols)
         jz      near .return
 
-        mov rdx, r10
+        mov edx, r10d
 
         ; -- expand_right_edge
 
         push    rcx
         shl     rcx,1                           ; output_cols * 2
         sub     rcx,rdx
         jle     short .expand_end
 
         mov     rax, r11
         test    rax,rax
@@ skipping 16 matching lines @@
 
         add     rsi, byte SIZEOF_JSAMPROW
         dec     rax
         jg      short .expandloop
 
 .expand_end:
         pop     rcx                             ; output_cols
 
         ; -- h2v1_downsample
 
-        mov     rax, r12        ; rowctr
+        mov     eax, r12d       ; rowctr
         test    eax,eax
         jle     near .return
 
         mov     rdx, 0x00010000         ; bias pattern
         movd    xmm7,edx
         pcmpeqw xmm6,xmm6
         pshufd  xmm7,xmm7,0x00          ; xmm7={0, 1, 0, 1, 0, 1, 0, 1}
         psrlw   xmm6,BYTE_BIT           ; xmm6={0xFF 0x00 0xFF 0x00 ..}
 
         mov     rsi, r14        ; input_data
@@ skipping 82 matching lines @@
 
         align   16
         global  EXTN(jsimd_h2v2_downsample_sse2) PRIVATE
 
 EXTN(jsimd_h2v2_downsample_sse2):
         push    rbp
         mov     rax,rsp
         mov     rbp,rsp
         collect_args
 
-        mov     rcx, r13
+        mov     ecx, r13d
         shl     rcx,3                   ; imul rcx,DCTSIZE (rcx = output_cols)
         jz      near .return
 
         mov     rdx, r10
 
         ; -- expand_right_edge
 
         push    rcx
         shl     rcx,1                           ; output_cols * 2
         sub     rcx,rdx
@@ skipping 20 matching lines @@
 
         add     rsi, byte SIZEOF_JSAMPROW
         dec     rax
         jg      short .expandloop
 
 .expand_end:
         pop     rcx                             ; output_cols
 
         ; -- h2v2_downsample
 
-        mov     rax, r12        ; rowctr
+        mov     eax, r12d       ; rowctr
         test    rax,rax
         jle     near .return
 
         mov     rdx, 0x00020001         ; bias pattern
         movd    xmm7,edx
         pcmpeqw xmm6,xmm6
         pshufd  xmm7,xmm7,0x00          ; xmm7={1, 2, 1, 2, 1, 2, 1, 2}
         psrlw   xmm6,BYTE_BIT           ; xmm6={0xFF 0x00 0xFF 0x00 ..}
 
         mov     rsi, r14        ; input_data
@@ skipping 73 matching lines @@
         jg      near .rowloop
 
 .return:
         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