pxenv: save away the PXE return code so COMBOOT can return it

PXELINUX itself doesn't actually use the PXE return code, but the
COMBOOT interface is supposed to return it.  Accordingly, make sure it
is stashed away so we can return it; for code that doesn't care, it
just writes a dedicated status variable which can be safely ignored.

diff --git a/comboot.inc b/comboot.inc
index 35cc7f9..df9bb00 100644 (file)
--- a/comboot.inc
+++ b/comboot.inc
@@ -446,8 +446,8 @@ comapi_pxecall:
                mov es,P_ES
                mov di,P_DI
                call pxenv
+               mov ax,[PXEStatus]
                mov P_AX,ax
-               clc
                ret
 %else
 comapi_pxecall equ comapi_err                  ; Not available

diff --git a/pxelinux.asm b/pxelinux.asm
index 8be844f..c4feee2 100644 (file)
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -1712,6 +1712,7 @@ pxenv:
                push bx
 .jump:         call 0:0
                add sp,6
+               mov [cs:PXEStatus],ax
                add ax,-1                       ; Set CF unless AX was 0
 
 %if USE_PXE_PROVIDED_STACK == 0
@@ -1722,6 +1723,8 @@ pxenv:
                ; except for testing it against zero (and setting CF),
                ; which we did above.  For anything else,
                ; use the Status field in the reply.
+               ; For the COMBOOT function, the value is saved in
+               ; the PXEStatus variable.
                popad
                cld                             ; Make sure DF <- 0
                ret
@@ -1729,6 +1732,12 @@ pxenv:
 ; Must be after function def due to NASM bug
 PXEEntry       equ pxenv.jump+1
 
+               section .bss
+               alignb 2
+PXEStatus      resb 2
+               
+               section .text
+
 ;
 ; getfssec: Get multiple clusters from a file, given the starting cluster.
 ;