pkarashchenko commented on a change in pull request #5192:
URL: https://github.com/apache/incubator-nuttx/pull/5192#discussion_r782072589
##########
File path: arch/risc-v/src/common/riscv_swint.c
##########
@@ -116,6 +134,26 @@ static void dispatch_syscall(void)
" ecall" /* Return from the syscall */
);
}
+#else
+static void dispatch_syscall(void)
+{
+ asm volatile
+ (
+ " addi sp, sp, -4\n" /* Create a stack frame to hold ra */
Review comment:
Should be relatively simple by:
```
#define STR_INSTR(n) #n
#define INSTR(n) STR_INSTR(n)
#ifdef CONFIG_ARCH_RV32
# define REGLOAD lw
# define REGSTORE sw
#else
# define REGLOAD ld
# define REGSTORE sd
#endif
```
and then
```
static void dispatch_syscall(void)
{
asm volatile
(
" addi sp, sp, -4\n" /* Create a stack frame to hold ra */
" " INSTR(REGSTORE) " ra, 0(sp)\n" /* Save ra in the stack frame */
" la t0, g_stublookup\n" /* t0=The base of the stub lookup
table */
" slli a0, a0, 3\n" /* a0=Offset for the stub lookup
table */
" add t0, t0, a0\n" /* t0=The address in the table */
" " INSTR(REGLOAD) " t0, 0(t0)\n" /* t0=The address of the stub for
this syscall */
" jalr ra, t0\n" /* Call the stub (modifies ra) */
" " INSTR(REGLOAD) " ra, 0(sp)\n" /* Restore ra */
" addi sp, sp, 4\n" /* Destroy the stack frame */
" mv a2, a0\n" /* a2=Save return value in a0 */
" li a0, 3\n" /* a0=SYS_syscall_return (3) */
" ecall" /* Return from the syscall */
);
}
```
##########
File path: arch/risc-v/src/common/riscv_swint.c
##########
@@ -116,6 +134,26 @@ static void dispatch_syscall(void)
" ecall" /* Return from the syscall */
);
}
+#else
+static void dispatch_syscall(void)
+{
+ asm volatile
+ (
+ " addi sp, sp, -4\n" /* Create a stack frame to hold ra */
Review comment:
Should be relatively simple by:
```
#define STR_INSTR(n) #n
#define INSTR(n) STR_INSTR(n)
#ifdef CONFIG_ARCH_RV32
# define REGLOAD lw
# define REGSTORE sw
#else
# define REGLOAD ld
# define REGSTORE sd
#endif
```
and then
```
static void dispatch_syscall(void)
{
asm volatile
(
" addi sp, sp, -4\n" /* Create a stack frame to hold ra */
" " INSTR(REGSTORE) " ra, 0(sp)\n" /* Save ra in the stack frame */
" la t0, g_stublookup\n" /* t0=The base of the stub lookup
table */
" slli a0, a0, 3\n" /* a0=Offset for the stub lookup
table */
" add t0, t0, a0\n" /* t0=The address in the table */
" " INSTR(REGLOAD) " t0, 0(t0)\n" /* t0=The address of the stub for
this syscall */
" jalr ra, t0\n" /* Call the stub (modifies ra) */
" " INSTR(REGLOAD) " ra, 0(sp)\n" /* Restore ra */
" addi sp, sp, 4\n" /* Destroy the stack frame */
" mv a2, a0\n" /* a2=Save return value in a0 */
" li a0, 3\n" /* a0=SYS_syscall_return (3) */
" ecall" /* Return from the syscall */
);
}
```
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