OS_Develop/FreeDOS
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sys: fix gcc build, int86 has to preserve ds

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The int86 function is used to call interrupt 21h
service 32h in the reset_drive function. This
function returns a pointer using the ds register.
ds will usually point into the DOS data segment
then (for our kernel). However, the compiler
assumed ds to be unchanged.
This commit is contained in:
C. Masloch 2022-12-31 14:32:08 +01:00 committed by Kenneth J Davis
parent bb1bbbb1cb
commit bf085a7ed6
1 changed files with 2 additions and 2 deletions
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4
sys/sys.c
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@ -121,8 +121,8 @@ struct _diskfree_t {
int int86(int ivec, union REGS *in, union REGS *out)
{
/* must save sp for int25/26 */
asm("mov %5, (1f+1); jmp 0f; 0:mov %%di, %%dx; mov %%sp, %%di;"
"1:int $0x00; mov %%di, %%sp; sbb %0, %0" :
asm("mov %5, (1f+1); jmp 0f; 0:push %%ds; mov %%di, %%dx; mov %%sp, %%di;"
"1:int $0x00; mov %%di, %%sp; pop %%ds; sbb %0, %0" :
"=r"(out->x.cflag),
"=a"(out->x.ax), "=b"(out->x.bx), "=c"(out->x.cx), "=d"(out->x.dx) :
"q"((unsigned char)ivec), "a"(in->x.ax), "b"(in->x.bx),