ref: 0b81becf6915c7c54d266f8cc170fd8db58bb6a8
parent: 00e6f81a080c81828854db16160d8b58a5cd8ca9
author: 9ferno <gophone2015@gmail.com>
date: Tue Dec 14 23:53:13 EST 2021
check that the buffer does not overflow UPE
--- a/os/pc64/bindings.s
+++ b/os/pc64/bindings.s
@@ -104,10 +104,13 @@
NEXT
TEXT fthread(SB), 1, $32 /* ( n a fd -- n2 ) */
- MOVQ(PSP), CX
PUSH(TOP)
- MOVQ CX, TOP /* ( n a fd -- n a fd a ) */
- CALL inup(SB)
+ MOVQ 16(PSP), TOP
+ MOVQ 8(PSP), CX
+ PUSH(TOP)
+ MOVQ CX, TOP /* ( n a fd -- n a fd n a ) */
+
+ CALL bufinup(SB)
MOVQ TOP, CX
POP(TOP)
CMPQ CX, $0
@@ -130,10 +133,13 @@
* Hence, need 32 bytes on the stack
*/
TEXT fthwrite(SB), 1, $32 /* ( n a fd -- n2|-1 ) */
- MOVQ(PSP), CX
PUSH(TOP)
- MOVQ CX, TOP /* ( n a fd -- n a fd a ) */
- CALL inup(SB)
+ MOVQ 16(PSP), TOP
+ MOVQ 8(PSP), CX
+ PUSH(TOP)
+ MOVQ CX, TOP /* ( n a fd -- n a fd n a ) */
+
+ CALL bufinup(SB)
MOVQ TOP, CX
POP(TOP)
CMPQ CX, $0
--- a/os/pc64/forth.s
+++ b/os/pc64/forth.s
@@ -168,6 +168,29 @@
MOVQ $1, TOP
RET
+/*
+callable by UP using forth macro entries to check address
+ ( n a -- -1|0|1 )
+ argument 1 in TOP = address
+ return value in TOP
+ -1 0 1
+ if UP < address && address+n < UPE
+ return 0 within range
+ else if address < UP
+ return -1 below UP
+ else if UPE < address+n
+ return 1 above UP
+ */
+TEXT bufinup(SB), 1, $-4
+ MOVQ (PSP), CX
+ ADDQ CX, TOP
+ CMPQ CX, UPE
+ JGT aboveupe
+ CMPQ TOP, UP
+ JLT belowup
+ MOVQ $0, TOP
+ RET
+
TEXT reset(SB), 1, $-4
MOVQ UP, RSP
ADDQ $RSTACK_END, RSP