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ia16-elf-gcc: use new SS != DGROUP support for int21_syscall(.)

This commit is contained in:
Tee-Kiah Chia 2020-04-18 01:19:38 +08:00 committed by Kenneth J Davis
parent 5ec1e993b4
commit 26626f2fed
1 changed files with 13 additions and 1 deletions
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14
kernel/inthndlr.c
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@ -71,7 +71,19 @@ struct HugeSectorBlock {
/* functions with SS != DGROUP. The code for this function happens to */
/* to compile under gcc-ia16 to correctly-behaving code _for now_. But */
/* it will be better to be able to guarantee this. -- tkchia 20191207 */
/* Update: I added experimental SS != DGROUP support, and a __seg_ss */
/* address space qualifier, to gcc-ia16 around January 2020. This */
/* function now uses these if available. In particular, the iregs *irp */
/* structure will always be on the stack, so (as far as the calling */
/* convention permits) the function can treat the irp pointer as a */
/* 16-bit pointer relative to SS. -- tkchia 20200417 */
#if defined __GNUC__ && defined __IA16_FEATURE_ATTRIBUTE_NO_ASSUME_SS_DATA
__attribute__((no_assume_ss_data))
VOID ASMCFUNC int21_syscall(iregs __seg_ss * irp, ...)
#else
VOID ASMCFUNC int21_syscall(iregs FAR * irp)
#endif
{
Int21AX = irp->AX;
@ -150,7 +162,7 @@ VOID ASMCFUNC int21_syscall(iregs FAR * irp)
/* Get DOS-C release string pointer */
case 0xff:
#ifndef __GNUC__
#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));