Call the BIOS through thunks that keep t1 to the jump

src/ldo.c

@@ -47,21 +47,14 @@
 */
 
 #ifdef LUA_TARGET_PSX
+#include "lpsxbios.h"
 struct JmpBuf { void * regs[12]; };
-static inline int syscall_setjmp(struct JmpBuf *buf) {
-    register int n asm("t1") = 0x13;
-    __asm__ volatile("" : "=r"(n) : "r"(n));
-    return ((int (*)(struct JmpBuf * buf))0xa0)(buf);
-}
-
-static inline __attribute__((noreturn)) void syscall_longjmp(struct JmpBuf *buf, int ret) {
-    register int n asm("t1") = 0x14;
-    __asm__ volatile("" : "=r"(n) : "r"(n));
-    ((void (*)(struct JmpBuf *, int))0xa0)(buf, ret);
-    __builtin_unreachable();
-}
-#define LUAI_THROW(L,c)         syscall_longjmp(&(c)->b, 1)
-#define LUAI_TRY(L,c,a)         if (syscall_setjmp(&(c)->b) == 0) { a }
+LUAI_PSX_BIOS_THUNK(setjmp, 0xa0, 0x13)
+LUAI_PSX_BIOS_EXTERN int __psxlua_bios_setjmp(struct JmpBuf *buf) __attribute__((returns_twice));
+LUAI_PSX_BIOS_THUNK(longjmp, 0xa0, 0x14)
+LUAI_PSX_BIOS_EXTERN void __psxlua_bios_longjmp(struct JmpBuf *buf, int ret) __attribute__((noreturn));
+#define LUAI_THROW(L,c)         __psxlua_bios_longjmp(&(c)->b, 1)
+#define LUAI_TRY(L,c,a)         if (__psxlua_bios_setjmp(&(c)->b) == 0) { a }
 #define luai_jmpbuf             struct JmpBuf
 #else
 #include <setjmp.h>
@@ -99,12 +92,9 @@ static void seterrorobj (lua_State *L, int errcode, StkId oldtop) {
 
 
 #ifdef LUA_TARGET_PSX
-static inline void abort() {
-    register int n asm("t1") = 0x40;
-    __asm__ volatile("" : "=r"(n) : "r"(n));
-    ((void (*)())0xa0)();
-    __builtin_unreachable();
-}
+LUAI_PSX_BIOS_THUNK(abort, 0xa0, 0x40)
+LUAI_PSX_BIOS_EXTERN void __psxlua_bios_abort(void) __attribute__((noreturn));
+#define abort() __psxlua_bios_abort()
 #else
 #include <stdlib.h>
 #endif

src/lpsxbios.h

@@ -0,0 +1,33 @@
+/*
+** BIOS calls for the PlayStation target.
+** Each call goes through a two-instruction thunk, `j 0xa0` with t1 set in its
+** delay slot, emitted in every file that includes this header as a weak symbol
+** in its own COMDAT section, so the linker keeps one copy of each. To the
+** compiler the thunk is a plain function: t1 cannot be reused before the jump,
+** and the BIOS returns straight to the caller.
+*/
+
+#ifndef lpsxbios_h
+#define lpsxbios_h
+
+#include <stddef.h>
+
+#define LUAI_PSX_BIOS_THUNK(name, table, number) \
+    __asm__(".pushsection .text.__psxlua_bios_" #name ",\"axG\",@progbits,__psxlua_bios_" #name ",comdat\n" \
+            ".weak __psxlua_bios_" #name "\n" \
+            ".type __psxlua_bios_" #name ", @function\n" \
+            ".set push\n.set noreorder\n" \
+            "__psxlua_bios_" #name ":\n" \
+            "    j " #table "\n" \
+            "    li $t1, " #number "\n" \
+            ".set pop\n" \
+            ".size __psxlua_bios_" #name ", . - __psxlua_bios_" #name "\n" \
+            ".popsection\n");
+
+#ifdef __cplusplus
+#define LUAI_PSX_BIOS_EXTERN extern "C"
+#else
+#define LUAI_PSX_BIOS_EXTERN extern
+#endif
+
+#endif

src/luaconf.h

@@ -211,18 +211,13 @@
 */
 #if defined(LUA_LIB) || defined(lua_c)
 #ifdef LUA_TARGET_PSX
-static inline void syscall_write(int fd, const void * buf, size_t count) {
-    register int n asm("t1") = 0x03;
-    __asm__ volatile("" : "=r"(n) : "r"(n));
-    ((void (*)(int, const void *, size_t))0xa0)(fd, buf, count);
-}
-static inline void syscall_putchar(int c) {
-    register int n asm("t1") = 0x3c;
-    __asm__ volatile("" : "=r"(n) : "r"(n));
-    ((void (*)(int))0xa0)(c);
-}
-#define luai_writestring(s,l)	syscall_write(1, (s), (l))
-#define luai_writeline()	syscall_putchar('\n')
+#include "lpsxbios.h"
+LUAI_PSX_BIOS_THUNK(write, 0xa0, 0x03)
+LUAI_PSX_BIOS_EXTERN size_t __psxlua_bios_write(int fd, const void * buf, size_t count);
+LUAI_PSX_BIOS_THUNK(putchar, 0xa0, 0x3c)
+LUAI_PSX_BIOS_EXTERN void __psxlua_bios_putchar(int c);
+#define luai_writestring(s,l)	__psxlua_bios_write(1, (s), (l))
+#define luai_writeline()	__psxlua_bios_putchar('\n')
 #else
 #include <stdio.h>
 #define luai_writestring(s,l)	fwrite((s), sizeof(char), (l), stdout)