From 3a3bd78ff4ed8dc52cb20dbe1490f46064ea42ab Mon Sep 17 00:00:00 2001
From: Mirek Kratochvil <exa.exa@gmail.com>
Date: Wed, 2 Aug 2023 21:28:45 +0200
Subject: [PATCH] it computs

---
 macros.s |  4 ++-
 uskel.s  | 88 +++++++++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 80 insertions(+), 12 deletions(-)

diff --git a/macros.s b/macros.s
index fcb80eb..8bc05da 100644
--- a/macros.s
+++ b/macros.s
@@ -9,7 +9,9 @@
 .endm
 
 .macro continue
-	enter %rdi
+	mov %rsi, %rax
+	mov %rbp, %rsi
+	enter %rax
 .endm
 
 .macro thunkenv arg, dest
diff --git a/uskel.s b/uskel.s
index d558856..dad9bc5 100644
--- a/uskel.s
+++ b/uskel.s
@@ -43,8 +43,7 @@ _uskel_start:
 	# save the memory ptr
 	mov %rdi, _memory_state
 
-	mov $0, %rsi # no result for main
-	mov $0, %rdi # set continuation to exit
+	mov $0, %rsi # set continuation to exit
 	enter %r15 # run the program
 
 # Simple values and boxed machine integers
@@ -145,22 +144,89 @@ THU_scavenge:
 # Actual code!
 #
 
+# || -> cont
 .makethunk main
-	# push a thunk for main_exit
 	mov _memory_state, %r15
-	mov %r15, %r14 # backup for later
+
+	# push a new integer
+	mov %r15, %r11 # backup first arg
+	movq $INT_code, 0x00(%r15)
+	movq $100, 0x08(%r15)
+	add $0x10, %r15
+
+	# push another new integer
+	mov %r15, %r12 # backup second arg
+	movq $INT_code, 0x00(%r15)
+	movq $23, 0x08(%r15)
+	add $0x10, %r15
+
+	# push the plus
+	mov %r15, %r13 # backup plus
+	movq $plus, 0x00(%r15)
+	movq $2, 0x08(%r15)
+	mov %r11, 0x10(%r15)
+	mov %r12, 0x18(%r15)
+	add $0x20, %r15
+
+	# push a cont thunk for main_exit
+	mov %r15, %r14 # backup cont thunk
 	movq $main_exit, 0x00(%r15)
 	movq $1, 0x08(%r15)
-	mov %rdi, 0x10(%r15)
+	mov %rsi, 0x10(%r15)
 	add $0x18, %r15
-	mov %r15, _memory_state
-	# continue 123
-	movq $INT_code, (%rbp)
-	movq $123, 0x8(%rbp)
-	mov %rbp, %rsi
-	enter %r14
 
+	mov %r15, _memory_state
+
+	# evaluate into main_exit
+	mov %r14, %rsi
+	enter %r13
+
+# exitcode -> | cont (unused, should be 0) |
 .makethunk main_exit
 	mov 0x8(%rsi), %rdi
 	mov $0x3c, %rax
 	syscall # exit %rdi
+
+# | arg1 | arg2 | -> cont
+.makethunk plus
+	# push a thunk for finishing the plus
+	mov _memory_state, %r15
+	mov %r15, %r14 # plus_step1 origin
+	movq $plus_step1, 0x00(%r15)
+	movq $3, 0x08(%r15)
+	mov 0x18(%rbp), %rax
+	mov %rax, 0x10(%r15)
+	mov %rbp, 0x18(%r15)
+	mov %rsi, 0x20(%r15)
+	add $0x28, %r15
+	mov %r15, _memory_state
+
+	# evaluate arg0
+	mov %r14, %rsi
+	enter 0x10(%rbp)
+
+# arg0 -> | arg1 | ret | cont |
+.makethunk plus_step1
+	# this is guaranteed to be entered only once (it's a cont), so we can rewrite the thunk in place
+	mov 0x10(%rbp), %rax
+	movq $plus_fini, 0x00(%rbp)
+	mov %rsi, 0x10(%rbp)
+
+	mov %rbp, %rsi # continue on the rewritten thunk
+	enter %rax # evaluate arg1
+
+# arg1 -> | arg0 | ret | cont |
+.makethunk plus_fini
+	mov 0x8(%rsi), %rax # arg1
+	mov 0x10(%rbp), %rsi
+	add 0x8(%rsi), %rax # + arg0
+
+	mov 0x18(%rbp), %rsi # rewrite the resulting thunk
+	movq $INT_code, 0x00(%rsi)
+	mov %rax, 0x08(%rsi)
+	# result is in rsi already
+	enter 0x20(%rbp)
+
+# Q: are there gonna be functions that have both the argument AND the cont?
+# A: No, either stuff is entered as return-continuation (takes res) or as forward call (takes cont)
+# (needs validation)