From fe465ec81d5f686147e47d9addd683b6ce28de3a Mon Sep 17 00:00:00 2001
From: julianb0 <spectral@os-k.eu>
Date: Thu, 16 May 2019 17:11:22 +0200
Subject: [PATCH] stack and function calls

---
 instr/INSTRS   |  6 ++++++
 instr/instrs.c | 37 ++++++++++++++++++++++++++++++++++---
 karch/decd.c   |  1 +
 karch/main.c   |  7 ++++++-
 4 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/instr/INSTRS b/instr/INSTRS
index 8720789..9e751ef 100644
--- a/instr/INSTRS
+++ b/instr/INSTRS
@@ -50,6 +50,12 @@ push r
 
 pop r
 
+call r
+call i
+call m
+
+ret
+
 cli
 sti
 
diff --git a/instr/instrs.c b/instr/instrs.c
index f006d3b..383b7d7 100644
--- a/instr/instrs.c
+++ b/instr/instrs.c
@@ -93,7 +93,7 @@ IMPL_START_1(push)
         _except(ctx, E_STK, "RSP above RBP");
     }
 
-    writemem64(ctx, v1, ctx->r[RSP]);
+    writemem64(ctx, v1, ctx->r[RSP].val);
     ctx->r[RSP].val -= 8;
 }
 IMPL_END;
@@ -107,12 +107,43 @@ IMPL_START_1(pop)
     if (ctx->r[RSP].val >= ctx->r[RBP].val) {
         _except(ctx, E_STK, "RBP above RSP");
     }
-    
-    v1 = readmem64(ctx, ctx->r[RSP]);
+
     ctx->r[RSP].val += 8;
+    v1 = readmem64(ctx, ctx->r[RSP].val);
 }
 IMPL_OUT;
 
+IMPL_START_1(call)
+{
+    if (ctx->r[RSP].val % 8 > 0 || ctx->r[RBP].val % 8 > 0) {
+       _except(ctx, E_STK, "Misaligned stack REGS");
+    }
+
+    if (ctx->r[RSP].val > ctx->r[RBP].val) {
+        _except(ctx, E_STK, "RSP above RBP");
+    }
+
+    writemem64(ctx, ctx->r[RIP].val, ctx->r[RSP].val);
+    ctx->r[RSP].val -= 8;
+    ctx->r[RIP].val = v1;
+}
+IMPL_END;
+
+IMPL_START_0(ret)
+{
+    if (ctx->r[RSP].val % 8 > 0 || ctx->r[RBP].val % 8 > 0) {
+       _except(ctx, E_STK, "Misaligned stack REGS");
+    }
+
+    if (ctx->r[RSP].val >= ctx->r[RBP].val) {
+        _except(ctx, E_STK, "RBP above RSP");
+    }
+
+    ctx->r[RSP].val += 8;
+    ctx->r[RIP].val = readmem64(ctx, ctx->r[RSP].val);
+}
+IMPL_END;
+
 IMPL_START_0(cli)
 {
     CHK_SUPERV();
diff --git a/karch/decd.c b/karch/decd.c
index bf171d3..d0ee409 100644
--- a/karch/decd.c
+++ b/karch/decd.c
@@ -64,6 +64,7 @@ void decode(ctx_t *ctx)
     ushort c = ctx->get(ctx);
     
     if (c == 0xFFFF) {
+        log("0x%016lX: stop\n", rip);
         _except(ctx, E_SHT, "Shutdown INSTR");
     }
 
diff --git a/karch/main.c b/karch/main.c
index ab3e5ab..472ebb3 100644
--- a/karch/main.c
+++ b/karch/main.c
@@ -8,7 +8,12 @@ ushort fwprog[] = {
     I_MOV_R_I, RBP, A_IMM32, FWSTACK>>16, FWSTACK&0xFF,
     I_MOV_R_I, RSP, A_IMM32, FWSTACK>>16, FWSTACK&0xFF,
 
-    I_PUSH_I, A_IMM16, 0xDDEE,
+    I_CALL_I, A_IMM32, (MEMOFF+0x13)>>16, (MEMOFF+0x13)&0xFF,
+    I_ADD_R_I, RAX, A_IMM16, 1,
+    0xFFFF,
+    
+    I_ADD_R_I, RBX, A_IMM16, 1,
+    I_RET,
 
 /*
     I_MOV_M_I, A_MEM, RBP, A_IMM16, 0xAC,