1 files changed, 24 insertions, 18 deletions
diff --git a/zap/source/amd64/mem/fndbyte.S b/zap/source/amd64/mem/fndbyte.S
index 9298b73..af2ee84 100644
--- a/zap/source/amd64/mem/fndbyte.S
+++ b/zap/source/amd64/mem/fndbyte.S
@@ -5,40 +5,46 @@
 .globl zap_fndbyte
 
 zap_fndbyte:
- # rax: Address of the current element.
- # rdi: Address of the first element.
- # rsi: Address of the element after the last element.
- # rdx: Byte value.
- # rcx: Current byte.
+# Address of the current element:
+#define addr %rax
+# Address of the first element:
+#define start %rdi
+# Address of the element after the last element:
+#define afterbuf %rsi
+# Byte value:
+#define cmp %dl
+# Current byte:
+#define val %cl
 
- movq %rdi,%rax
+ movq start,addr # addr = start
 
- addq %rdi,%rsi
+ addq start,afterbuf # afterbuf += start
 
 # Iterate over the array:
 .loop:
 
 # Check if we have reached the end of the array:
- cmpq %rax,%rsi
- je .nfnd
+ cmpq addr,afterbuf # if (addr == afterbuf)
+ je .nfnd # goto nfnd
 
 # Check if we have found the byte value:
- movb (%rax),%cl
- cmpb %cl,%dl
- je .fnd
+ movb (addr),val # val = *addr
+ cmpb val,cmp # if (val == cmp)
+ je .fnd # goto fnd
 
 # Continue to the next byte:
- incq %rax
- jmp .loop
+ incq addr # ++addr
+ jmp .loop # goto loop
 
 # Found:
 .fnd:
 
- subq %rdi,%rax
- ret
+ # Get the offset of the byte:
+ subq start,addr # addr -= start
+ ret # return addr
 
 # Not found:
 .nfnd:
 
- movq $0xFFFFFFFFFFFFFFFF,%rax
- ret
+ movq $0xFFFFFFFFFFFFFFFF,addr # addr = FFFFFFFFFFFFFFFF
+ ret # return addr