add Intel syntax alternatives to all gcc inline assembly

hdr/portab.h

@@ -162,15 +162,15 @@ static inline void enable(void)
 static inline unsigned short getCS(void)
 {
   unsigned short ret;
-  asm volatile("mov %%cs, %0" : "=r"(ret));
+  asm volatile("{ mov %%cs, %0 | mov %0, cs }" : "=r"(ret));
   return ret;
 }
 
 #define _SS getSS()
 static inline unsigned short getSS(void)
 {
   unsigned short ret;
-  asm volatile("mov %%ss, %0" : "=r"(ret));
+  asm volatile("{ mov %%ss, %0 | mov %0, ss }" : "=r"(ret));
   return ret;
 }
 extern char DosDataSeg[];

kernel/chario.c

@@ -152,7 +152,7 @@ STATIC void fast_put_char(unsigned char chr)
     _AL = chr;
     __int__(0x29);
 #elif defined(__GNUC__)
-    asm volatile("int $0x29":: "a"(chr):"bx");
+    asm volatile("{ int $0x29 | int 0x29 }":: "a"(chr):"bx");
 #elif defined(I86)
     asm
     {

kernel/inthndlr.c

@@ -178,7 +178,7 @@ VOID ASMCFUNC int21_syscall(iregs FAR * irp)
 #if !defined __GNUC__ || defined  __IA16_FEATURE_ATTRIBUTE_NO_ASSUME_SS_DATA
           irp->DX = FP_SEG(os_release);
 #else  /* TODO: remove this hacky SS != DGROUP workaround  --tkchia 20191207 */
-          asm volatile("movw %%ds, %0" : "=g" (irp->DX));
+          asm volatile("{ movw %%ds, %0 | mov %0, ds }" : "=g" (irp->DX));
 #endif
           irp->AX = FP_OFF(os_release);
       }

kernel/main.c

@@ -840,7 +840,7 @@ STATIC void CheckContinueBootFromHarddisk(void)
 
   {
 #if __GNUC__
-    asm volatile("jmp $0,$0x7c00");
+    asm volatile("{ jmp $0,$0x7c00 | jmp 0,0x7c00 }"::);
 #else
     void (far *reboot)(void) = (void (far*)(void)) MK_FP(0x0,0x7c00);
 

kernel/prf.c

@@ -75,7 +75,7 @@ void put_console(int c)
     __int__(0xe6);
 #elif defined(__GNUC__)
     asm volatile(
-      "int $0xe6\n"
+      "{ int $0xe6 | int 0xe6 }"
       : /* outputs */
       : /* inputs */ "a"(0x13), "e"(FP_SEG(buff)), "d"(FP_OFF(buff))
     );
@@ -126,7 +126,7 @@ void put_console(int c)
   fastComPrint(c);
 #endif
 #elif defined(__GNUC__)
-  asm volatile("int $0x29" : : "a"(c) : "bx");
+  asm volatile("{ int $0x29 | int 0x29 }" : : "a"(c) : "bx");
 #elif defined(I86)
   __asm
   {

sys/sys.c

@@ -108,14 +108,25 @@ struct _diskfree_t {
 int int86x(int ivec, union REGS *in, union REGS *out, struct SREGS *s)
 {
   /* must save sp for int25/26 */
-  asm("mov %7, %%cs:(1f+1); jmp 0f; 0:"
+  asm("{"
+      "mov %7, %%cs:(1f+1); jmp 0f; 0:"
       "mov %%di, %%dx; mov %%sp, %%di;"
       "push %%di; push %%di;"
       /* push twice to work both for int 25h/26h and int 21h */
       "1:int $0x00; pop %%di; pop %%di;"
       /* second pop always reads the correct SP value.
          the first pop may read the FL left on stack. */
-      "mov %%di, %%sp; sbb %0, %0" :
+      "mov %%di, %%sp; sbb %0, %0;"
+      " | "
+      "mov byte ptr cs:[1f+1], %7; jmp 0f; 0:"
+      "mov dx, di; mov di, sp;"
+      "push di; push di;"
+      /* push twice to work both for int 25h/26h and int 21h */
+      "1:int 0x00; pop di; pop di;"
+      /* second pop always reads the correct SP value.
+         the first pop may read the FL left on stack. */
+      "mov sp, di; sbb %0, %0;"
+      "}" :
       "=r"(out->x.cflag),
       "=a"(out->x.ax), "=b"(out->x.bx), "=c"(out->x.cx), "=d"(out->x.dx),
       "=e"(s->es), "=Rds"(s->ds) :
@@ -140,7 +151,11 @@ int intdos(union REGS *in, union REGS *out)
 
 int intdosx(union REGS *in, union REGS *out, struct SREGS *s)
 {
-  asm("push %%ds; mov %%bx, %%ds; int $0x21; pop %%ds; sbb %0, %0":
+  asm("{"
+      "push %%ds; mov %%bx, %%ds; int $0x21; pop %%ds; sbb %0, %0\n"
+      " | "
+      "push ds; mov ds, bx; int 0x21; pop ds; sbb %0, %0\n"
+      "}" :
       "=r"(out->x.cflag), "=a"(out->x.ax) :
       "a"(in->x.ax), "c"(in->x.cx), "d"(in->x.dx),
       "D"(in->x.di), "S"(in->x.si), "b"(s->ds), "e"(s->es) :