Version 0.4.00.4.0

1 files changed, 63 insertions, 0 deletions

diff --git a/tests/fixtures/frame-pointer.s b/tests/fixtures/frame-pointer.s
new file mode 100644
index 0000000..6c6934b
--- /dev/null
+++ b/tests/fixtures/frame-pointer.s
@@ -0,0 +1,63 @@
+; Build/run from examples/:
+;   ../utils/mcpu-as -o frame-pointer.o frame-pointer.s
+;   ../utils/mcpu-ld --stack-size=512 -o frame-pointer frame-pointer.o
+;   ../utils/mcpu-run --int-reg=r64@0x00008 frame-pointer
+;
+; Expected output: 42
+;
+; LibCPU optional frame-pointer and dynamic STACK allocation example.
+;
+; demo(5) builds a fixed frame, creates a 24-byte dynamic object below it,
+; accesses a fixed local through FP while SP is moving, and returns 42 in
+; the canonical r64 return register.
+
+.text
+_start_life:
+        LDI     r64@0x00000, 5
+        ADJSP   -16                      ; 16-byte ABI argument block
+        STSP    0, r64@0x00000
+        CALL    demo
+        ADJSP   16
+        MOV     r64@0x00008, r64@0x7fff8
+        HALT
+
+demo:
+        PUSHFP
+        SETFP
+        ADJSP   -16
+
+        ; First explicit argument.  With FP in use the layout is:
+        ;   FP+0  saved caller FP
+        ;   FP+8  return PC
+        ;   FP+16 first explicit argument
+        LDFP    r64@0x00100, 16
+
+        ; Fixed local at FP-8.
+        STFP    -8, r64@0x00100
+        LEAFP   r64@0x00108, -8
+
+        ; Save the current stack top as a dynamic-scope mark.
+        LEASP   r64@0x00110, 0
+
+        ; Dynamically reserve 24 bytes: new_SP = old_SP - 24.
+        LDI     r64@0x00118, 24
+        PSUB    r64@0x00120, r64@0x00110, r64@0x00118
+        SETSP   r64@0x00120
+
+        ; Put 37 in the dynamic object at current SP.
+        LDI     r64@0x00128, 37
+        LEASP   r64@0x00130, 0
+        STOREP  r64@0x00130, r64@0x00128
+
+        ; FP-relative access is stable although SP moved dynamically.
+        LDFP    r64@0x00138, -8
+        LOADP   r64@0x00140, r64@0x00130
+        IADD    r64@0x7fff8, r64@0x00138, r64@0x00140
+
+        ; Restore the nested dynamic scope explicitly.
+        SETSP   r64@0x00110
+
+        ; Destroy the complete frame below FP, restore caller FP and return.
+        RESTSP
+        POPFP
+        RET