Add stubs for many libc functions, and a few implemenations too

1 files changed, 53 insertions, 0 deletions

diff --git a/src/lib/libc/setjmp.s b/src/lib/libc/setjmp.s
new file mode 100644
index 0000000..164cc5b
--- /dev/null
+++ b/src/lib/libc/setjmp.s
@@ -0,0 +1,53 @@
+[GLOBAL setjmp]
+setjmp:
+	; Store general purpose registers
+	; (in new stack frame)
+	mov [esp+4], eax
+	mov [esp+8], ebx
+	mov [esp+12], ecx
+	mov [esp+16], edx
+	mov [esp+20], edi
+	mov [esp+24], esi
+	mov [esp+28], ebp
+	mov [esp+32], esp
+
+	; Store flags
+	pushf
+	pop eax
+	mov [esp+36], eax
+
+	; Store return address
+	mov eax, [esp]
+	mov [esp+40], eax
+
+	; return 0
+	xor eax, eax
+	ret
+
+
+[GLOBAL longjmp]
+longjmp:
+	; on previous stack, resume return address
+	mov eax, [esp+32]
+	mov ebx, [esp+40]
+	mov [eax], ebx
+
+	; resume flags
+	mov eax, [esp+36]
+	push eax
+	popf
+
+	; load return value in eax
+	mov eax, [esp+44]
+	; resume geneal purpose registers, except eax/esp
+	mov ebx, [esp+8]
+	mov ecx, [esp+12]
+	mov edx, [esp+16]
+	mov edi, [esp+20]
+	mov esi, [esp+24]
+	mov ebp, [esp+28]
+
+	; resume previous esp
+	mov esp, [esp+32]
+	; return as if we were the setjmp call
+	ret